The Logical World of Puzzles

World Puzzle Championship 2011

2011-11-18T01:21:00.001+05:30

The 6th World Sudoku Championship and 20th World Puzzle Championship was held on 6th-10th November, 2011 in Eger, Hungary.

Championship Page

This is the first time the WSC and WPC was held as a combined event.

Team India
The national finals of the Indian Sudoku Championship and the Indian Puzzle Championship was held in June 2011. Unfortunately, Ritesh Gupta and Gaurav Korde were unable to attend the WSC, and Harmeet Singh was unable to attend the WPC. So, we were forced to go down the list and finally are team consisted of:

Sudoku Team
Sumit Bothra (Bengaluru)
Tejal Phatak (Mumbai)
Prasanna Seshadri (Mumbai)
Rohan Rao (Mumbai)

Puzzle Team
Rajesh Kumar (Bengaluru)
Rajib Ranjan Borah (Mumbai)
Tejal Phatak (Mumbai)
Rohan Rao (Mumbai)

I was very busy since I had three exams before my trip and have my entire end-semester examinations immediately after my trip, so I spent minimal time for puzzles. Not the best thing to do by a national champion but I was left with little choice.

Last year I stood 41st in WPC and my goal this year was to reach the top 25.

6th November, 2011 - 8th November, 2011
World Sudoku Championship 2011

9th November, 2011
We had a day before WPC began. A city tour to an ice cave seemed exciting but no one was prepared for the surprise that awaited us. Right in the midst of the cave, was held the WSC prize distribution and the photo session!

It was an excellent idea, and it went pretty smoothly. It was nice on the organisers part to do something different of this sort, yet, not overly change things.

10th November, 2011
The World Puzzle Championship 2011 began.

Round 1: In Memorium
It was a pretty ordinary start. Not too good, not too bad. Ulrich Voigt (Germany) outperformed everyone by a good margin.

Round 2: Assorted Puzzles
I started feeling weary and tired. Mental strain was winning over my body. I seemed very slow in a lot of puzzles this round, and I knew this was going to be a bad round. And it was.

Round 3: Cows
I'm usually good at recovering after bad rounds, and this was no exception. The 75-pointer Small Regions was my strength and I'm glad I could crack it. The 'Knight' puzzle had no solution, so I'm sure many players would've been affected.

Round 4: Borderless
Clueless in borderless. I do not know how other players felt about this round, but I had no strategy in this round. I was not comfortable with any variant, and I couldn't see a path other than guesswork in solving these puzzles. I wasn't even confident of getting a non-zero score.

During the first 15 minutes, I kept switching from one puzzle to another, having no progress at all. Then, I found a clue in Easy As ABC (big) and I solved it. That encouraged me to do the smaller one too, and that was all. Palmer Mebane (USA) scored 295. I wonder...

Round 5: Evergreens
I thought this was one round where I could really score well. I was quite disappointed with my performance. Got stuck in a couple of puzzles, made an error in one. On my day, I could've done much much better.

Round 6: Board Games
The concept and puzzles was very nice. It was fun solving them. Lets not talk about the scores though.

Round 7: Naval Puzzles
By this time, all of us were tired and we knew we had no hope to getting into the top 15 in the team rankings. We just solved this for the fun of it.

Not a very good first day for me. I was ranked around 40th at the end of Day 1. Too difficult to get into top 25 from here. I just hoped to better my last year's rank of 41.

11th November, 2011
Day 2 of WPC.

Round 8: Screen Test
This was the best round of WPC. A screen test with animations! Some beautiful puzzles, and great ideas. A huge round of applause followed the test which shows most people enjoyed the test. I hope some players benefitted by the Screen Test I had organised on LMI a week before :-)

In terms of scores, Annick Weyzig (Netherlands) and Jason Zuffranieri (USA) topped with 185 points. I scored 125 and at least I beat Palmer Mebane (USA) and Ulrich Voigt (Germany) in one round!

Round 9: Sprint
Anyone loves Numberlink and Train puzzles? Try solving these ones. These were some tough ones for me. I think some of them were the toughest I've ever solved.

Round 10: Divide And Conquer
I love this puzzle type. And the puzzles that appeared, were simply superb. Even the easier ones, had some fantastic logic to it.

Round 11: Magic 11
This round was themed around the number '11'. It was a good round for me.

Round 12: Hungaricum
A couple of good rounds earlier, but this round was not good. I was floating around the mid-30's and I had a good chance to squeeze myself in the top 30 with one round left.

Round 13: Innovative
Another average round.

Round 14: Best Of
The last individual round. And I messed it up. I got the lowest points among the players in the top 35 and I lost three ranks directly.

Bad finish, but I'm glad I was able to better my rank. I finished 34th.

WPC Playoffs
The format of the playoffs was interesting. Top 10 puzzlers start solving based on a time difference in proportion to their scores. The last 3 players to finish the first 3 puzzles are eliminated. Then the last 2 players to finish the next 3 puzzles are eliminated. Then a fight to the finish with the last 3 puzzles.

Ulrich Voigt (Germany): 7-time World Puzzle Champion. He had a big lead, and would surely win if the playoffs went smoothly.

Palmer Mebane (USA): Beating Thomas Snyder at USPC is no joke. Beating him again at WPC is no luck. I was pretty confident he would make it to the podium.

Thomas Snyder (USA): Performed poorly in Day 2, and lost chunks of points. But, you could never count him out till the end.

The fight for the title had to be between these three players. It was unlikely someone else would win.

Hideaki Jo (Japan), Bram de Laat (Netherlands), Peter Hudak (Slovakia), Nikola Zivanovic (Serbia), Roland Voigt (Germany), Wei-Hua Hwang (USA) and Neil Zussman (UK) complete the top 10. Michael Ley (Germany) finished 7th in the standings, but surprisingly (and unfortunately), he was not in the official team, and hence could not participate in the playoffs.

The playoffs began and it was going like everyone had expected. Ulrich had a one puzzle lead for a major portion and Palmer was catching up quickly. Thomas was unable to catch up to them. It all seemed to going well, and Ulrich reached the second last puzzle, with a one puzzle lead. Then the tables turned. Ulrich kept making a mistake. He was desperately erasing and trying. Palmer on the other hand, completed the puzzle and was the first one to reach the last puzzle. A few minutes later, he had won. Ulrich was still stuck on the puzzle. Now even Thomas reached the puzzle and solved it too! Just a few seconds after Thomas reached the last puzzle, was Ulrich able to complete his second last one. But he beat Thomas in the last puzzle to take silver.

Playoff Results

1. Palmer Mebane (USA)
2. Ulrich Voigt (Germany)
3. Thomas Snyder (USA)

Individual Results

1. Ulrich Voigt (Germany) - 5085
2. Palmer Mebane (USA) - 4769
3. Thomas Snyder (USA) - 4546

Indian Results

34. Rohan Rao - 2898
85. Rajesh Kumar - 1691
91. Rajib Ranjan Borah - 1495
97. Tejal Phatak - 1143

Complete Individual Results

Team Results

1. USA - 20447
2. Germany - 20304
3. Japan - 18026

Complete Team Results

Overall, it was a great championship. The puzzles, the rounds, and the format and organisation was as good as it could get. With WSC and WPC combined, it involves a lot of effort and work, and the Hungarians did a wonderful job.

I am happy with my performance. Top 25 would have been ideal, but at least I was able to improve my rank.

Congrats to Palmer Mebane for winning his maiden WPC title.

Congrats to Thomas Snyder for finishing on the podium in both events. Congrats to Thomas Snyder, Hideaki Jo and Nikola Zivanovic (and Michael Ley) for making the playoffs (top 10) in both events.

It was good meeting up with old friends and new ones, and I hope this trend of WSC+WPC continues (maybe with a little more rest time or little less puzzles!)

World Sudoku Championship 2011

2011-11-14T17:00:00.001+05:30

The 6th World Sudoku Championship and 20th World Puzzle Championship was held on 6th-10th November, 2011 in Eger, Hungary.

Championship Page

This is the first time the WSC and WPC was held as a combined event.

Team India
The national finals of the Indian Sudoku Championship and the Indian Puzzle Championship was held in June 2011. Unfortunately, Ritesh Gupta and Gaurav Korde were unable to attend the WSC, and Harmeet Singh was unable to attend the WPC. So, we were forced to go down the list and finally are team consisted of:

Sudoku Team
Sumit Bothra (Bengaluru)
Tejal Phatak (Mumbai)
Prasanna Seshadri (Mumbai)
Rohan Rao (Mumbai)

Puzzle Team
Rajesh Kumar (Bengaluru)
Rajib Ranjan Borah (Mumbai)
Tejal Phatak (Mumbai)
Rohan Rao (Mumbai)

I was very busy since I had three exams before my trip and have my entire end-semester examinations immediately after my trip, so I spent minimal time for puzzles. Not the best thing to do by a national champion but I was left with little choice.

Last year I stood 15th in WSC and my goal this year was to reach the top 10. I really thought I could make it this time, especially with my improvement in the LMI tests and other championship results.

6th November, 2011
We reached Eger around 6pm, rested for a while, and went for the Welcome Party. All of us were quite tired and sleepy after an 8-hour journey and being 4.5 hours behind our usual time-zone, we immediately hit the sac.

7th November, 2011
The World Sudoku Championship 2011 began.

Part 1: Wrong Puzzles
Many players were of the opinion that this is not a 'sudoku-solving' round. I was indifferent. I didn't think it was completely random, nor was I convinced it was the best round to start a WSC with.

The puzzles were a pleasant surprise. There were a good mix of grids, with various fonts, styles, sizes and overall, it was a fun round. I don't think many people would have complained after the round, but surely, it was better than expected for most players.

In terms of scores, I started very poorly with a mere 68 points in this round compared to the highest 150 by David McNeill (UK).

Part 2: Sudoku Pieces
It took me a while in understanding the puzzle when I was studying the booklet. Once it was clear, I wasn't comfortable with this. I'm not very good at these kind of sudoku rounds. When it was announced that we had to place the pieces on the sheet itself, I thought I was doomed. I just wanted the round to begin and then end, as soon as possible. I was glad this round had partial scoring.

When the round started, it was a little comforting that there were 81 clues and no empty cells. I was slow to start, but after getting a few pieces, I was quickly able to crack the grid. I was mighty pleased with myself as (I think) this was the first time I said 'Finish!' at a WSC :-)

Part 3: Easy Classics
This round went quite average for me. Tiit Vunk (Estonia) scored an exceptional 605 points.

Part 4: Halved Squares Sudoku
I had a bad feeling about this round. I did not practise at all (not even the ones of the Hungarian championship) and I was quite sure this would be one of the bad rounds.

I will not say it was good, but it went better than I expected. A below average score though.

Thomas Snyder (USA) took a considerable lead from many top players after this round.

Part 5: Sudoku Central Clues
This round was good, and I was able to move up a few ranks. I think I was 17th or 18th after this round at the end of Day 1 of Individuals.

Part 6: Circle Sudoku (Team)
The concept of this round was well thought of. The execution, even better. I always enjoy solving linked puzzles and this was very exciting. We were able to solve 4 sudokus and missed one more by a few seconds.

Part 7: Vasarely Sudoku (Team)
Another nice team round and we were quite happy we were able to finish it in time. A lot of other teams finished it too.

8th November, 2011
Day 2 of WSC. I needed all my rounds to go extremely well in order to be in the top 10. Tough chance, but possible.

Part 8: Decorated Sudoku
This was one of the big rounds. I started well and scored 465 points. Just for argument sake, I equalled Thomas Snyder (USA) in this round!

Part 9: Sprint Sudoku
A fast-paced round. I need to practise these Sprint rounds. I tend to do better in longer rounds. Probably because of my mental stamina.

Part 10: Sudoku Mix
Another big round. This round pulled me down a bit. I got stuck in Tetris and Increasing Roundabout and lost some time.

Part 11: Not Easy Classics
I got the highest score in Hard Classics in WSC 2010 in Philadelphia. Well, fluke rarely happens twice!

Part 12: 3D Sudoku
I'm not particularly good at solving Cube Sudokus, but I surprised myself and was able to solve it in time. So, second time in one WSC, I said 'Finish!'. Pretty cool!

Part 13: Weakest Link (Team)
A standard weakest link round where each player of the team solves an individual puzzle and then goes to the team table. Our team finished this round and we were confident of finishing in the top 10 in the team rankings.

WSC Playoffs
I finished 12th. Missed the playoffs by about 80 points. The playoffs consisted of a good set of players.

The format of the playoffs was interesting. Top 10 puzzlers start solving based on a time difference in proportion to their scores. The last 3 players to finish the first 3 puzzles are eliminated. Then the last 2 players to finish the next 3 puzzles are eliminated. Then a fight to the finish with the next 4 puzzles.

Thomas Snyder (USA): World Sudoku Champion 2007, 2008. He had a big lead and would surely win if the playoffs went smoothly for him.

Jan Mrozowski (Poland): World Sudoku Champion 2009, 2010. He was probably the biggest threat to Thomas.

Tiit Vunk (Estonia) and Kota Morinishi (Japan) were looking very strong in the championship.

Florian Kirch (Germany), Jan Novotny (Czech Republic), Nikola Zivanovic (Serbia), Michael Ley (Germany), Hideaki Jo (Japan) and Jakub Ondrousek (Czech Republic) complete the top 10.

The playoffs started with a shock. Jan Mrozowski was stuck on the second puzzle while everyone else proceeded. He probably had some problem on his end. Kota Morinishi was racing through the puzzles and catching up with Thomas who was always one table ahead. Thomas kept the lead and calmly finished all the puzzles. Kota finished second, and Tiit, with a slight stumble midway finished 3rd. Hideaki, after starting 9th, finished a creditable 4th.

Playoff Results

1. Thomas Snyder (USA)
2. Kota Morinishi (Japan)
3. Tiit Vunk (Estonia)

Individual Results

1. Thomas Snyder (USA) - 3760
2. Jan Mrozowski (Poland) - 3525
3. Tiit Vunk (Estonia) - 3459

Indian Results

12. Rohan Rao - 2983
44. Sumit Bothra - 2154
54. Tejal Phatak - 1966
71. Prasanna Seshadri - 1725
101. Rajesh Kumar - 1314

Complete Individual Results

Team Results

1. Germany - 16436
2. Czech Republic - 16181
3. USA - 14488

8. India - 11708

Complete Team Results

Overall, it was a great championship. The sudokus, the rounds, and the format and organisation was as good as it could get. With WSC and WPC combined, it involves a lot of effort and work, and the Hungarians did a wonderful job.

I am happy with my performance. Top 10 would have been ideal, but at least I was close. Maybe next time.

Congrats to Thomas Snyder for winning his 3rd WSC title. He has been very consistent throughout the year and is a deserving winner.

It was good meeting up with old friends and new ones, and I hope this trend of WSC+WPC continues.

Logic Masters India - Screen Test 2

2011-11-01T19:27:00.000+05:30

Logic Masters India announces the second edition of Screen Test. It will be held on 1st-4th November.

I authored last year's Screen Test 1 with Deb Mohanty. This year, I authored it alone. I learnt a lot from last year and was quite happy with the response. I'm hoping this time it turns out to be better and bigger since there are some changes that have been made based on the feedback.

Championship Page
Download Screen Test Guide
Forum

For new-comers as well as regulars, it is very important to read through the Screen Test Guide and go through the examples on the webpage before starting the test to have maximum benefit of the system.

You may ask any queries on the forum or here.

I hope you enjoy the puzzles and relish the 35-minute puzzle-ride!

Logic Masters India - October 2011 Puzzle Test

2011-10-15T11:11:00.000+05:30

Logic Masters India announces the October 2011 Puzzle Test 'Double Decathlon'. It will be held on 15th-16th October, 2011.
The author of the puzzles is Thomas Snyder. You will find a lot of practise puzzles on his blog 'The Art Of Puzzles'.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password will be available when you start the test.
Forum

Results will be declared on 17th October.

Logic Masters India - October 2011 Sudoku Test

2011-10-01T11:50:00.002+05:30

Logic Masters India announces the October 2011 Sudoku Test 'A or B'. It will be held on 1st-2nd October, 2011.
The author of the puzzles is Deb Mohanty.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password will be available when you start the test.
Forum

The list of sudokus that will appear in the test are:

Odd Sudoku
Extra Region Sudoku
Greater Sudoku
Lesser Sudoku
Even Sudoku
Small Neighbours Sudoku
Sequence Sudoku
Palindrome Sudoku
Marked Quadro Sudoku
Multiplication Table Sudoku
Neighbouring Sudoku
Sum 10 Sudoku
Multiple Sudoku
Touchy Sudoku
Antiknight Sudoku
XV Sudoku
Kropki Sudoku
Consecutive Sudoku
Fiver Sudoku
Skyscraper Sudoku
Outside Sudoku
Odd/Even View Sudoku

Please read the instructions carefully. This is a different type of sudoku test.

Results will be declared on 3rd October.

US Sudoku Championship 2011

2011-09-24T21:44:00.003+05:30

The US Sudoku Championship 2011 was held on 24th September, 2011.

View Championship Page

You can download the booklets from the website.

USA Results

1. Jonathan Rivet - 255
2. Jason Zuffranieri - 230
3. Jim Schneider - 224

International Results

1. Branko Ceranic (Serbia) - 289.29
2. Bastien Vial-Jaime (France) - 280
3. Hideaki Jo (Japan) - 275
4. Ko Okamoto (Japan) - 260.17
5. Rohan Rao (India) - 260

Complete Results

Logic Masters India - September 2011 Sudoku Test

2011-09-08T11:20:00.002+05:30

Logic Masters India announces the September Sudoku Test 'Crazy Arrows'. It was held on 10th-11th September, 2011.
I am the author!

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is CrazyzarCArrowsworrA
Forum

The list of sudokus that appeared in the test are:

0-9 Arrow Sudoku
Count Arrow Sudoku
Difference Arrow Sudoku
Incomplete Arrow Sudoku
Missing Arrow Sudoku
Parted Arrow Sudoku
Product Arrow Sudoku
Skyscraper Arrow Sudoku
Sum Arrow Sudoku
Symmetric Arrow Sudoku
Wrong Arrow Sudoku

Results

1. Thomas Snyder (USA) - 925
2. Nikola Zivanovic (Serbia) - 805
3. Kota Morinishi (Japan) - 760
4. Palmer Mebane (USA) - 740
5. Branko Ceranic (Serbia) - 715
6. Sinchai R (Thailand) - 700
7. Zafer Huseyin Ergan (Turkey) - 680
8. Sylvain Caudmont (France) - 660
9. Hideaki Jo (Japan) - 635
10. Peter Hudak (Slovakia) - 635

Best Indians

32. Rakesh Rai - 485
34. Amit Sowani - 465
42. Jaipal Reddy - 410
44. Sudhir Shankar Raman - 400
56. Rajesh Kumar - 350

Complete Results

Congrats to Thomas for winning Crazy Arrows with a big lead. Congrats to Nikola and Kota for 2nd and 3rd respectively.

I got the idea of Crazy Arrows last year, and I'm glad I could finally conduct this test. The test was tough, and some of the sudokus were very challenging for players.

0-9 was my favourite variation of this set, and also was the first variant that I had thought of.

Count was the easiest sudoku of the set and 90% of the players solved it.

Difference was difficult to start, but once you get few numbers correctly, the grid solves quickly.

Incomplete was another easy sudoku and this was Deb's idea that I worked on.

Missing was the toughest of the set. Guesswork was needed in multiple places and only 5 players were able to solve it. This is now the least solved individual sudoku on LMI so far. Maybe you can try to crack it!

Parted was not easy. After getting a few initial numbers, there is a little guesswork required.

Product was one of my favourite sudokus. The idea was taken from USA where it appeared in WSC 2010.

Skyscraper was relatively easy compared to the other sudokus.

Sum 1 was tough. As Jason mentioned in his post on LMI, it had a very 'Killer feeling'.

Sum 2 was my favourite. And it also is the favourite of the players. Most people commented on this grid and it has the maximum rating too, so, I consider this the cream of the set.

Symmetric was the one sudoku that couldn't make this test a neat one. It was worth 75 points and I apologize for the mistake on my part. It was much tougher and deserved a lot more points. It was also very difficult and a lot of players might've been affected by this and I regret the mistake.

Wrong was one of my top 3 sudokus of the set. Many players might have had a hiccough while solving when seeing a '9' on an arrow and a '1' in a circle. But I guess most of the players realised that it does work that way :-)

I thank all the participants for removing time and participating in Crazy Arrows and I hope you'll enjoyed at least a few of the sudokus. Hope to see you again in 'Crazier Arrows'!

Logic Masters India - September 2011 Puzzle Test

2011-09-05T23:29:00.002+05:30

Logic Masters India announces the September 2011 Puzzle Test 'Sprint Test'. It was held on 3rd-4th September, 2011.
The author of the puzzles is Bastien Vial-Jaime (Ours Brun).

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is SroSis201246
Forum

The list of puzzles that appeared in the test are:

Akari
Fillomino
Fortress
Galaxies
Heyawacky
Horse Snake
LITS
Masyu
Nurikabe
Pointing Evens Sudoku
Slitherlink
Snail
Star Battle
Tapa
Yajilin

Results

1. Palmer Mebane (USA) - 348
2. Thomas Snyder (USA) - 345
3. Ko Okamoto (Japan) - 336
4. Nagata Yuta (Japan) - 312
5. Hideaki Jo (Japan) - 306
6. Psyho (Poland) - 306
7. Zoltan Horvath (Hungary) - 297
8. Kota Morinishi (Japan) - 288
9. Phillip Edwards (Australia) - 287
10. Michael Ley (Germany) - 285

Best Indians

46. Rakesh Rai - 180
49. Rohan Rao - 175
72. Amit Sowani - 140
97. Jaipal Reddy - 115
112. Harmeet Singh - 105

Complete Results

Another new dimension to LMI! A fast-paced test where every second counts. Puzzles were excellent. Full credit to Bastien for this fantastic set.
You make one error, and you lose chunks of relative time. Its quite disappointing that I wasn't able to finish all the 15 puzzles, especially when there are players who do it in half your time.
Congrats to Palmer and Thomas (I guess you'll are continuing the battle here too) and the Japanese for their excellent results.

Sudokucup 6 (Part 2)

2011-09-05T23:09:00.000+05:30

The sixth Sudokucup was held in two parts. Sudokucup 6 Part 1 was held on 23rd-24th July, 2011.
Sudokucup 6 Part 2 was held on 3rd-4th September, 2011.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is KNASUQ91?3JMEP

The list of sudokus that appeared in the test are:

1. Classic Sudoku
2. Diagonal Sudoku
3. Irregular Sudoku
4. Extra Region Sudoku
5. Antiknight Sudoku
6. Sequences Sudoku
7. Kropki Sudoku
8. All Even All Odd Sudoku
9. Surprise Sudoku
10. Clock-Faces Sudoku
11. More-Less Sudoku
12. Arrow Sudoku
13. Little Killer Sudoku
14. Decimal Killer Sudoku

Results

1. Jakub Ondrousek (Czech Republic) - 300 (01:10)
2. Jan Mrozowski (Czech Republic) - 300 (01:17)
3. Tiit Vunk (Estonia) - 300 (01:22)
4. Michael Ley (Germany) - 300 (01:24)
5. Jason Zuffranieri (USA) - 300 (01:25)
6. Hideaki Jo (Japan) - 300 (01:27)
7. Branko Ceranic (Serbia) - 300 (01:30)
8. Rishi Puri (India) - 300 (01:35)
9. Chen Cen (China) - 300 (01:36)
10. Nikola Zivanovic (Serbia) - 300 (01:38)

Best Indians

8. Rishi Puri - 300 (01:35)
15. Rohan Rao - 300 (01:46)
58. Jaipal Reddy - 227
69. Prasanna Seshadri - 211
83. Rakesh Rai - 171

Complete Results

Sudokucup 6 Part 2 was definitely much easier than Part 1. 27 Players finished all sudokus within the 2 hours compared to just 7 in Part 1.

Now that both parts of SC6 are over, I wonder who is the winner of 'Sudokucup 6'?

US Puzzle Championship 2011

2011-08-26T23:02:00.000+05:30

The 2011 US Puzzle Championship was held on 27th August, 2011.

View Championship Page

USA Results

1. Palmer Mebane (USA) - 415
2. Thomas Snyder (USA) - 349
3. William Blatt (USA) - 309

Complete Results

This was my first 'complete' USPC. Since it is midnight in India during USPC, I dozed off last two years.

Congrats to Palmer Mebane for ending Thomas Snyder's five-year reign at the USPC! Both of them have been performing consistently well in championships throughout the year, and I'm sure they would be among the top guns at the WPC in Hungary.

You can read more about the championship on the champions' blogs:
Thomas Snyder's views
Palmer Mebane's views

Looking forward to meet you'll and your team in Hungary.

Logic Masters India - August 2011 Puzzle Test

2011-08-21T11:13:00.003+05:30

Logic Masters India announces the August 2011 Puzzle Test 'Japanese Puzzle Land'. It was held on 20th-21st August, 2011.
The authors of the puzzles are Yosuke Imai, Atsumi Hirose, Takeya Saikachi and Daisuke Takei.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Download Solution Booklet
Forum

The list of puzzles that appeared in the test are:

Sudoku
Kakuro
Fillomino
Numberlink
Slitherlink
Masyu
Heyawake
Akari
Shikaku
Hitori
Shakashaka
Mochikoro
Yajilin

Results

1. Thomas Snyder (USA) - 550
2. Kota Morinishi (Japan) - 434
3. Tarotaro (Japan) - 426
4. Endo Ken (Japan) - 426
5. Volxa (Japan) - 424
6. Ko Okamoto (Japan) - 421
7. Palmer Mebane (USA) - 410
8. Shinichi Aoki (Japan) - 398
9. Psyho (Poland) - 381
10. Yukkuri (Japan) - 356

Best Indians

37. Rakesh Rai - 266
58. Rohan Rao - 219
87. Rajesh Kumar - 178
101. Amit Sowani - 160
105. Harmeet Singh - 150

Complete Results

Excellent set of puzzles. For the first time, Japanese authored an LMI and test and what a huge success! It saw maximum number of participants in an LMI test!
Congrats to the Japanese authors and also to the Japanese participants who had some tremendous results. And needless to say, congrats to Thomas for winning yet another LMI test.

Rules of 'Heyawake'

2011-08-17T16:51:00.001+05:30

Blacken some cells so that all remaining cells are connected orthogonally. No two black cells can share an edge. Any single horizontal or vertical line of white cells cannot traverse more than one thick line. Numbers indicate the amount of black cells in that region.

EXAMPLE:

UNIQUE SOLUTION:

Logic Masters India - August 2011 Sudoku Test

2011-08-06T20:43:00.003+05:30

Logic Masters India announces the August Sudoku Test 'Sudoku City'. It was held on 6th-7th August, 2011.
The author of the puzzles is Nikola Zivanovic.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is SkyIsTheLIMIT
Forum

Results

1. Yuhei Kusui (Japan) - 93
2. Thomas Snyder (USA) - 83
3. Branko Ceranic (Serbia) - 81
4. Jason Zuffranieri (USA) - 79
5. Jakub Hrazdira (Czech Republic) - 79
6. WaterlooMathie (Canada) - 77
7. Hideaki Jo (Japan) - 77
8. Kota Morinishi (Japan) - 73
9. Bastien Vial-Jaime (France) - 71
10. Rohan Rao (India) - 71

Best Indians

10. Rohan Rao - 71
17. Rakesh Rai - 57
53. Neeraj Mehrotra - 33
54. Harmeet Singh - 32
83. Prasanna Seshadri - 22

Complete Results

Before
Skyscraper Sudoku variants. This promises to be an exciting contest. The variation look good and Nikola has never disappointed me :-)
I'm been performing below par in the last couple of tests, maybe I can redeem with this one.

After
What a city! Nikola has proved he's the best architect among puzzlers by building this beautiful city. I'm sure most citizens who entered the city did not want to leave!

Logic Masters India - July 2011 Puzzle Test 2

2011-08-02T10:14:00.034+05:30

Logic Masters India announces the July Puzzle Test 2 'Magic Cube'. It was held on 29th-30th July, 2011.
The authors of the puzzles are the puzzle-makers of the 20th World Puzzle Championship (which will be held in November).

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is WPCandWSCinHungary2011
Forum

The list of puzzles that appeared in the test are: (In cube format)

1. Magic Snail
2. Hitori
3. Cave
4. Dutch Loop
5. Sudoku
6. Capsules
7. Heyawake
8. Fillomino
9. Slalom
10. Star Battle
11. Crosswords

Results

1. Thomas Snyder (USA) - 1226
2. Ko Okamoto (Japan) - 1085
3. Palmer Mebane (USA) - 1080
4. Peter Hudak (Slovakia) - 1065
5. Hideaki Jo (Japan) - 1045
6. Ulrich Voigt (Germany) - 950
7. Kota Morinishi (Japan) - 935
8. Nikola Zivanovic (Serbia) - 900
9. Jan Mrozowski (Poland) - 845
10. Shinichi Aoki (Japan) - 825

Best Indians

56. Rohan Rao - 510
68. Rajesh Kumar - 460
73. Rakesh Rai - 440
75. Amit Sowani - 430
79. Swaroop Guggilam - 420

Complete Results

Thanks to all the organisers of this test and the WPC for having this test. It is a very good set of puzzles, especially for those who will be present in Hungary for the WPC.

Sudokucup 6 (Part 1)

2011-07-24T12:24:00.002+05:30

The sixth Sudokucup will be held in two parts. Part 1 was held on 23rd-24th July, 2011. Players can participate in any one or both the parts.
The author of the puzzles is Jan Novotny.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is UWA61GA!711EXK

The list of sudokus that appeared in the test are:

1. Classic Sudoku
2. Diagonal Sudoku
3. Irregular Sudoku
4. Extra Region Sudoku
5. Antiknight Sudoku
6. Sequences Sudoku
7. Kropki Sudoku
8. All Even All Odd Sudoku
9. Surprise Sudoku
10. Clock-Faces Sudoku
11. More-Less Sudoku
12. Arrow Sudoku
13. Little Killer Sudoku
14. Decimal Killer Sudoku

Results

1. Jan Mrozowski (Poland) - 300 (01:10)
2. Hideaki Jo (Japan) - 300 (01:35)
3. Minfang Lin (China) - 300 (01:46)
4. Kota Morinishi (Japan) - 300 (01:49)
5. Florian Kirch (Germany) - 300 (01:52)
5. Bastien Vial-Jaime (France) - 300 (01:52)
7. SJ Kwak (South Korea) - 300 (01:55)
8. Vincent Bertrand (Belgium) - 286
9. Jakub Hrazdira (Czech Republic) - 274
10. Nikola Zivanovic (Serbia) - 273

Best Indians

14. Rohan Rao - 260
51. Rakesh Rai - 171
78. Prasanna Seshadri - 121
79. Akash Doulani - 121
80. Neeraj Mehrotra - 121

Complete Results

Logic Masters India - July 2011 Sudoku Test

2011-07-16T14:28:00.002+05:30

Logic Masters India announces the July Sudoku Test 'Fivefold'. It was held on 16th-17th July, 2011.
The author of the puzzles is Serkan Yurekli.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is inthememoryofmyFather
Forum

The list of sudokus that appeared in the test are:

1. Classic Sudoku (Solving Techniques)
2. Extra Region Sudoku
3. Outside Sudoku
4. Pandigital Sudoku
5. Distance Sudoku
6. Quadruple Sudoku
7. Crossnumber Sudoku
8. Number 5 Still Alive Sudoku
9. Numeral Sudoku
10. Odd Sum Sudoku
11. Quad Max Sudoku
12. Group Sum Sudoku
13. Musketry Sudoku
14. Killer Sudoku (Solving Techniques)
15. Triangles Sudoku
16. Odd-Even-Big-Small Sudoku
17. Thermometer Sudoku
18. Just One Cell Sudoku
19. Double Diagonal Sudoku

Results

1. Rishi Puri (India) - 1061.8
2. Jan Mrozowski (Poland) - 1022.0
3. Hideaki Jo (Japan) - 990.5
4. Thomas Snyder (USA) - 973.2
5. Kota Morinishi (Japan) - 972.4
6. Seungjae Kwak (South Korea) - 851.7
7. Jason Zuffranieri (USA) - 787.5
8. Don3232 (Taiwan) - 772.5
9. Nikola Zivanovic (Serbia) - 762.3
10. Vincent Bertrand (Belgium) - 745.6

Best Indians

1. Rishi Puri - 1061.8
11. Rohan Rao - 741.6
46. Tejal Phatak - 442.2
72. Rakesh Rai - 380.0
77. Himanshu Mittal - 367.0

Before
These sudoku types have been taken from the last five World Sudoku Championships. The set features many of my favourite sudoku types and I would be disappointed if I do not perform well.
Good luck to all participants!

After
Beautiful test. I think every sudoku had its own charm in solving and thats the mark of a good author.
I personally liked Group Sum and Quadruple the best of the set. I'm sure now everyone considers Serkan as a great sudoku author as well!
How about a Serkan Screen Test next?

Logic Masters India - July 2011 Puzzle Test

2011-07-09T11:07:00.004+05:30

Logic Masters India announces the July Puzzle Test 'Nikoli Selection 2'.
The author of the puzzles is Tom Collyer.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet 1
Download Puzzle Booklet 2 (Marathon Puzzles)
Password is Fi3VenOcee
Forum

The list of puzzles that will appear in the test are:

1. Akari
2. Fillomino
3. Hashiwokakero
4. Heyawake
5. Hitori
6. Kakuro
7. LITS
8. Masyu
9. Numberlink
10. Nurikabe
11. Ripple Effect
12. Shikaku
13. Slitherlink
14. Sudoku
15. Suraromu
16. Yajilin

Results

1. Hideaki Jo (Japan) - 492
2. Thomas Snyder (USA) - 431
3. Nagata Yuta (Japan) - 352
4. Jan Mrozowski (Poland) - 330
5. Tarotaro (Japan) - 320
6. Palmer Mebane (USA) - 315
7. Volxa (Japan) - 311
8. Kota Morinishi (Japan) - 310
9. Psyho (Poland) - 310
10. Jason Zuffranieri (USA) - 298

Best Indians

43. Rohan Rao - 215
84. Amit Sowani - 150
94. Rajesh Kumar - 140
100. Swaroop Guggilam - 130
115. Harmeet Singh - 105

Complete Results
There were totally 168 participants.

Before
This is the second set of Nikoli Selection on LMI. Tom Collyer had authored Nikoli Selection 1 in October 2010.
You will find lots of practise puzzles on Tom Collyer's Blog 'Detuned Radio'

This test will be very similar to the previous one with the format and puzzles the same. Hopefully, it will be a better than last time :-)
Looking forward to this test and good luck to all participants!

After
Very nice set of puzzles! Enjoyed every one of them.
Slitherlink and Kakuro were well-constructed, I lost a little time in these two puzzles.
Hitori and Sudoku were easy.
Nurikabe is a puzzle that I struggle in very often, but this time, I got it fairly quick. I guess I'm making some progress.
Numberlink is always fun.
Suraromu! The exclamation says it all! This is my choice of the best puzzle of the set. Brilliantly thought and beautifully executed, perfect for a Suraromu puzzle. Being a little experienced, I quickly realised how the top-left corner would be with straight lines and the rest just followed.
This is the first time I solved a Yajilin puzzle in a contest!
Fillomino was tricky while Akari was simple.
Masyu was the puzzle that realised snatched my chances of finishing all the 16 main puzzles. I dont know how I went wrong, but I had to erase thrice.
Ripple Effect is very enjoyable to me, I like the concept a lot.
Hashi and Rectangles were both tricky, and had some nice solving steps.

I'll solve the marathon puzzles on another lazy Sunday evening.
Overall, a good contest, with some really good puzzles.

Congrats to Hideaki Jo, who finished all the 16 main puzzles and the 3 marathon puzzles! With WPC coming soon, players have already started to make a mark!

Solving Star Battle: (Solved Example 1)

2011-07-02T22:49:00.000+05:30

Take a look at Puzzle No.189

Each region is represented by an alphabet for convenience. Refer to this while reading through.

Using Region E, R5C7 can be eliminated. Using region F, R6C5, R6C6 and R8C5 can be eliminated. Using region H, R7C2 and R6C3 can be eliminated.

Observe regions G,F and H. If R6C8 is a star, the both stars of region G will be in the 8th row, which results in stars in R7C1 and R7C3 for region H leading to a contradiction in Region F. Hence, R6C8 is NOT a star.

Now the puzzle becomes very easy. Using Region E, R4C7 can be eliminated. One out of R4C6 and R5C6 has to be a star and hence R4C5 and R5C5 is eliminated.

Using Region F, we get a star in R7C6. All adjacent cells is eliminated.

Using Column 7, we get stars in R1C7 and R3C7, followed by stars in R5C6 and R5C8. After eliminating the remaining cells of row 5, you should be able to finish the puzzle.

Other Solving Techniques

Logic Masters India - June 2011 Sudoku Test

2011-06-23T10:45:00.003+05:30

Logic Masters India announces the June 2011 Sudoku Test 'Logidoku'. It was held on 18th-19th June, 2011.
The authors of the puzzles are Zuzka Hromcova (zuziik) and Matus Demiger (greenhorn).

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is uKODiGOL
Forum

The list of sudokus that appeared in the test are:

1. Battleship Sudoku
2. Domino Sudoku
3. Easy As ABC Sudoku
4. Fence Sudoku
5. Japanese Sums Sudoku
6. Kakuro Sudoku
7. Kropki Sudoku
8. Pairs Sudoku
9. Skyscrapers Sudoku
10. Tapa Sudoku

Results

1. Nikola Zivanovic (Serbia) - 348
2. Michael Ley (Germany) - 260
3. Ulrich Voigt (Germany) - 260
4. Jan Mrozowski (Poland) - 257
5. Hideaki Jo (Japan) - 250
6. Jakub Hrazdira (Czech Republic) - 233
7. Seungjae Kwak (South Korea) - 231
8. Takuya Sugimoto (Japan) - 230
9. Psyho (Poland) - 222
10. Zoltan Horvath (Hungary) - 222

Best Indians

11. Rohan Rao - 215
50. Tejal Phatak - 120
55. Harmeet Singh - 115
59. Swaroop Guggilam - 112
77. Rakesh Rai - 88

Complete Results

Before
Looks to be an interesting set. Puzzles combined with sudokus would be advantageous to players who are comfortable with puzzles. Lets see if the results prove it.

After
A very nice set of sudokus (or puzzles!). I loved the Tapa 9x9 and the Easy As ABC 9x9.
Congrats to Nikola for the big victory! It is very rare to see Thomas not in the top 3. Congrats to Michael and Ulrich for a close fought 2nd and 3rd.

Indian Puzzle Championship 2011

2011-06-15T00:18:00.000+05:30

The Indian Puzzle Championship 2011 will consist of 13 regional rounds held in the months of January to March 2011. The top 3 from each of these regional rounds will be invited for the national finals on 12-Jun-2011. The team which will represent India at the World Sudoku Championship will be selected on the basis of the performance in the Indian Sudoku Championship National Final.

Championship Page
Forum

There are several ways in which you could qualify for a position in the National Finals.

You could be amongst the top 3 at one of the regional rounds.
You could be amongst the top 15 from the Online Qualifying round which will be held on date.

The 13 regional rounds will be held as a part of the college festivals in reputed colleges in different colleges across the country. The regional rounds will be held in the cities of Mumbai, Kharagpur, Rourkela, Goa, Guwahati, Bangalore, Kanpur, Hyderabad, Ranchi, Bhopal, Delhi, Roorkee and Pilani in the months from January to March. The regional round finals will be held between the top 60 participants from the region. The 60 finalists will be selected from Regional Prelims which will be open to all participants. For more details regarding the venue and dates of the regional round nearest to you please have a look at the Schedule.

The national finals was held on 12th June at Community Hall inside DRDO Complex, CV Raman Nagar, Bengaluru (Bangalore).

Download Instruction Booklet

10th June, 2011
I took a flight to Bengaluru and reached Rajesh's house around 6pm. After a brief nap, I spent some time with Rajesh's family and relaxed. Last year, I won the Indian Puzzle Championship (and the Indian Sudoku Championship) and going into this year's finals being the defending champion was not the easiest thing for me. There were a lot of first-timers due to the regional rounds and the regular group of good players were anyways there. These were my thoughts about some of the players

Amit Sowani: Has been itching to get back to participation after creating puzzles for previous IPCs. He has been the best performing Indian at WPC and could win the title this time.
Rajesh Kumar: 5-time national champion is a force that could shake me down. I considered him to be my biggest threat.
Rakesh Rai: Has been consistent and has beaten me in LMI Monthly Puzzle Tests. He could've been the dark horse.
Ritesh Gupta: Does not enjoy solving puzzles as much as sudoku but you can never count him out.
Tejal Phatak: Has been consistent and was part of the team last year.

Unfortunately, Amit could not make it to the event. Rakesh pulled out too. And, as expected, it turned out to be a battle between Rajesh and me (like last year), where I won IPC 2010 by just 40 points.

11th June, 2011
Indian Sudoku Championship

12th June, 2011
I was hoping to be in the Indian team at least, if not win the championship. The finals had a lot of new variations, so I was confident of making it in the top 3.

Round 1
Download Puzzle Booklet
This was a Sprint Round and we had to solve as many puzzles as possible in 60 minutes. It was a modest start by me as I could solve 13 whereas Rajesh solved 15 and took an 80-point lead.

Round 2
I had to do well in this round. And I did. I solved 4 puzzles worth 340 points and Rajesh solved 1 puzzle worth 120 points. 220 points more than Rajesh! Now, the IPC title was almost surely mine. But, one puzzle turned out to be incorrect. Both Rajesh and me spent time on the puzzle. The round had to be cancelled and it was the fairest possible decision. Of course, it was disadvantageous to me foregoing such a big lead, but then there was nothing I could do.

Round 3
Download Puzzle Booklet
The decider round. Rajesh had 80 points more than me. I had to come up with something spectacular to win. The round timing was increased from 60 minutes to 90 minutes. When the round started, my heart starting beating very fast and I started to get nervous. I really wanted to win. With confidence, speed and accuracy, I put all my puzzling skills into action and it did result in an extremely important performance. I completed all the 20 puzzles in 86 minutes, thus getting a 40 point time bonus. I couldn't have ended it better. I never ever thought I would be able to complete the round. I scored 740 and had a comfortable lead over Rajesh's 415 in the final round.

Results

1. Rohan Rao (Mumbai) - 1020
2. Rajesh Kumar (Bengaluru) - 775
3. Harmeet Singh (Bengaluru) - 555
4. Sumit Bothra (Kolkata) - 460
5. Ritesh Gupta (Delhi) - 460
6. Rajib Borah (Mumbai) - 445
7. Swaroop Guggilam (Mumbai) - 425
8. Tejal Phatak (Mumbai) - 405
9. Zalak Ghetia (Bengaluru) - 350
10. Prasanna Seshadri (Mumbai) - 350

Complete Results

I won IPC again. I won ISC and IPC in the same year again. So, that makes it four titles on a trot. I'm very happy and I've worked hard for this. I thank my family and friends for all the support.

As for the results, it may look like I won with a comfortable 245-point lead, but it was closer than it looks. Rajesh likes competing and he complimented me. His words 'I tried giving you a fight, but you were unbeatable today' mean a lot to me. Harmeet Singh's performance got lost in our battle, but I must say, a terrific performance by him. He could well be a contender for the title next year. Sumit and Ritesh had modest performances and always seem to be ranked one after the other!

Rajib Borah had an excellent Round 3 and had he done better in Round 1, he would surely have been ranked higher. Swaroop Guggilam almost made it to the top 4 with a good Round 1 and Round 3. A few silly mistakes cost him a few points and was pulled down to 7th. Tejal Phatak and Zalak Ghetia were the best performing women.

The puzzles were beautiful, some of them created by Foreign Puzzlers. It was organised very well, and ended successfully.

The entire event was co-ordinated by one man, Deb Mohanty, who spent a lot of time and effort in ensuring the success of the event.

Credits

I thank Rajesh Kumar, Deb Mohanty and their families for giving me accomodation. Special thanks to Deb Mohanty and his team (view credits) for organising this wonderful event which went very smoothly and was a huge success.

Indian Sudoku Championship 2011

2011-06-13T23:22:00.011+05:30

The Indian Sudoku Championship 2011 will consist of 14 regional rounds held in the months of January to March 2011. The top 3 from each of these regional rounds will be invited for the national finals on 11-Jun-2011. The team which will represent India at the World Sudoku Championship will be selected on the basis of the performance in the Indian Sudoku Championship National Final.

Championship Page
Forum

There are several ways in which you could qualify for a position in the National Finals.

You could be amongst the top 3 at one of the regional rounds.
You could be amongst the top 15 from the Online Qualifying round which will be held on date.

The 14 regional rounds will be held as a part of the college festivals in reputed colleges in different colleges across the country. The regional rounds will be held in the cities of Mumbai, Chennai, Kharagpur, Rourkela, Goa, Guwahati, Bangalore, Kanpur, Hyderabad, Ranchi, Bhopal, Delhi, Roorkee and Pilani in the months from January to March. The regional round finals will be held between the top 60 participants from the region. The 60 finalists will be selected from Regional Prelims which will be open to all participants. For more details regarding the venue and dates of the regional round nearest to you please have a look at the Schedule.

Download Instruction Booklet (Online Qualification)
Download Puzzle Booklet (Online Qualification)

The regional rounds went really well and it was nice to see so many participants in the online round too.

List of Qualifiers

The national finals was held on 11th June at Community Hall inside DRDO Complex, CV Raman Nagar, Bengaluru (Bangalore)

Download Instruction Booklet

10th June, 2011
I took a flight to Bengaluru and reached Rajesh's house around 6pm. After a brief nap, I spent some time with Rajesh's family and relaxed. Last year, I won the Indian Sudoku Championship (and the Indian Puzzle Championship) and going into this year's finals being the defending champion was not the easiest thing for me. There were a lot of first-timers due to the regional rounds and the regular group of good players were anyways there. These were my thoughts about some of the players

Gaurav Korde: Has been away for a while, but a great performance in Beijing shows how he can pull himself at critical times.
Rakesh Rai: Has been very consistent and I believed him to be the dark horse.
Rishi Puri: Last year's runner-up, who has been in tremendous form lately with his recent exploits in Beijing.
Ritesh Gupta: 3-time national champion would be raring to get his title back.
Sumit Bothra: Out of practise, but can deliver when needed.
Tejal Phatak: Has been consistently rising and offline events are her strength.

It was a big disappointment when Rishi had to cancel his trip. His absence at the finals meant a pillar went missing. Some people felt I should've been happy since a big contender of the title had pulled out. But I like competition and I've always enjoyed a fight, irrespective of the result. Adding to Rishi's absence, Rakesh and Jaipal too pulled out at the last moment thus thinning the competition to a great extent. I was very disappointed but I couldn't do much about it.

11th June, 2011

The competition hall was huge and as Sumit mentioned 'It gave the feel of a puzzle championship'. I felt comfortable and I was hoping to make it in the Indian team at least, if not win the championship.

Round 1
Download Puzzle Booklet
It was a perfect beginning for me. I was able to finish the round with a 1-minute time bonus. I was shell-shocked when the results came out to see I already had a 95-point lead over 2nd place Tejal and a 190-point lead over 3rd place Ritesh.

Round 2
Download Puzzle Booklet
I finished 6 of the 7 sudokus in 50 minutes and had 10 minutes to complete Odd-Even Frame. It was disappointing to miss the last one, but good enough to top the round and extend my lead.

Round 3
Download Puzzle Booklet
I never expected to complete this round, but I had a big advantage by finishing Equal Sum and Multiplication Table within 25 minutes. I even checked every 2x2 region of Equal Sum to make sure I didn't go wrong. I finished all the sudokus with a 5-minute bonus and this was when I was sure of retaining my ISC title.

Round 4
Download Puzzle Booklet
I wanted to win ISC by topping all four rounds and it went exactly as I would've liked. I spent more than 10 minutes on the 'very difficult' Touchy but couldn't crack it. I got the first Classic wrong with a silly error, but I topped the round with 350, just 20 more than Tejal!

Results

1. Rohan Rao (Mumbai) - 1895
2. Ritesh Gupta (Delhi) - 1155
3. Sumit Bothra (Kolkata) - 1140
4. Tejal Phatak (Mumbai) - 1105
5. Gaurav Korde (Mumbai) - 970
6. Prasanna Seshadri (Mumbai) - 765
7. Harmeet Singh (Bengaluru) - 740
8. Himanshu Mittal (Delhi) - 725
9. Akash Doulani (Kolkata) - 710
10. Rajesh Kumar (Bengaluru) - 670

Complete Results

Sumit Bothra and Deb Mohanty

Ritesh Gupta and Deb Mohanty

Rohan Rao and Deb Mohanty

Relieved, excited and happy, I won ISC 2011 and retained my title. I knew we were going to be given certificates but I had no idea there were trophies for the top 3. The certificates and trophies were both wonderful!

Looking at the results, Gaurav Korde had a disappointing day. Most of us expected him to be in the top 3. Tejal Phatak performed extremely well and so did debutant Prasanna Seshadri. Harmeet Singh had a fantastic weekend, too.

The sudokus were exceptionally good, especially Round 3. I felt the 6x6 Linked Sudokus of Round 1 were slightly tougher than what it should've been.
I liked Odd-Even View from Round 2, Mulitplication Table from Round 3 and Classic-Diagonal from Round 4.
All the rounds were well-timed, without any problems.

It was a wonderful event, had excellent puzzles, was organised infallibly and ended on a successful note.

The entire event was co-ordinated by one man, Deb Mohanty, who spent a lot of time and effort in ensuring the success of the event. Not only did he organise the event, he created every one of the sudokus of the championship. I wonder how he managed to do this all by himself. He must be super-man!

Credits

I thank Rajesh Kumar, Deb Mohanty and their families for giving me accomodation. Special thanks to Deb Mohanty and his team (view credits) for organising this wonderful event which went very smoothly and was a huge success.

Logic Masters India - June 2011 Puzzle Test

2011-06-05T11:30:00.002+05:30

Logic Masters India announces the June 2011 Puzzle Test 'Fillomino-Fillia'. It will be held on 4th-5th June, 2011.
The author of the puzzles are Grant Fikes (mathgrant) and Palmer Mebane (mellowmelon).

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password will be available when you start the test
Forum

Logic Masters India - May 2011 Sudoku Test

2011-06-05T11:13:00.004+05:30

Logic Masters India announces the May 2011 Sudoku Test 'Something Is Missing'. It was held on 28th-29th May, 2011.
The author of the puzzles is Jakub Hrazdira.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Forum

The list of sudokus that appeared in the test are:

1. Non-Consecutive Sudoku
2. Kropki Sudoku
3. Jigsaw Sudoku
4. Toroidal Sudoku
5. Number X Is Alive Sudoku
6. Incomplete Sums Sudoku
7. Draw A Jigsaw Sudoku
8. Missing Digit Sudoku
9. Hidden Sum Blackout Sudoku
10. Instructionless Sudoku

Results

1. Thomas Snyder (USA) - 437
2. Ulrich Voigt (Germany) - 400
3. Hideaki Jo (Japan) - 380
4. Michael Ley (Germany) - 380
5. Yuhei Kusui (Japan) - 370
6. Sylvain Caudmont (France) - 335
7. Nikola Zivanovic (Serbia) - 330
8. Psyho (Poland) - 330
9. Richard Hoffer (USA) - 320
10. David McNeill (UK) - 320

Best Indians

18. Rakesh Rai - 260
21. Rohan Rao - 240
45. Prasanna Seshadri - 145
46. Utkaarsh Somaiya - 145
64. Harmeet Singh - 115

Complete Results

Another tough set from Jakub. Beautifully constructed sudokus. Instructionless was lovely. I got the logic in about 20 seconds. The concept of 'missing' was used very neatly. Thanks Jakub for another exciting contest.

Logic Masters India - May 2011 Puzzle Test

2011-05-14T15:53:00.004+05:30

Logic Masters India announces the May 2011 Puzzle Test 'MAYnipulation'. It was held on 13th-14th May, 2011.
The author of the puzzles is Murat Can Tonta.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is 1_888_PUZZLES
Forum

Results

1. Palmer Mebane (USA) - 758
2. Ulrich Voigt (Germany) - 710
3. Thomas Snyder (USA) - 683
4. Shinichi Aoki (Japan) - 683
5. Hideaki Jo (Japan) - 643
6. Michael Ley (Germany) - 553
7. Kota Morinishi (Japan) - 533
8. Nikola Zivanovic (Serbia) - 505
9. Olivier (France) - 498
10. Nagata Yuta (Japan) - 480

Best Indians

23. Rohan Rao - 345
47. Amit Sowani - 255
59. Rakesh Rai - 165
65. Tejal Phatak - 125
77. Ravi Kumar - 60

Complete Results

Before
Interesting set of puzzles. Looking forward to it.

After
Nice tough puzzles. A below par performace by me, but enough to beat my country-mates.

Solving Along The Lines: 'Singular Cells'

2011-05-11T22:27:00.000+05:30

The best way to begin Along The Lines puzzles is by identifying 'Singular Cells', cells which can be touched by only one single clue, enabling you to draw a line from the clue to the cell.

Take a look at Puzzle No.30

Observe the two marked cells. R4C4 can be touched either by the '8' clue, or by the '3' clue. But R3C3 can only be touched by the '6' clue.

Hence we draw the line from the '6' clue to R3C3. Now observe R4C4, which was earlier not a singular cell.

R3C3 has become a singular cell since the '3' clue now cannot touch the cell. Hence it has to be touched by the '8' clue.

This is the best way to start and solve Along The Lines puzzles. In fact, many times you can solve the entire puzzle using this rule effectively.

Other Solving Techniques

Logic Masters India - April 2011 Sudoku Test

2011-04-29T11:35:00.003+05:30

Logic Masters India announces the April Sudoku Test. This test has been merged with the online qualification test for the Indian Sudoku Championship.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is Ki2sVeheMi
Forum

The list of sudokus that appeared in the test are:

1. Odd-Even Sudoku
2. Diagonal Sudoku
3. Extra Region Sudoku
4. XV Sudoku
5. Consecutive Sudoku
6. Trio Sudoku
7. Outside Sudoku
8. Inequality Sudoku
9. Irregular-Scattered Sudoku
10. Killer Sudoku
11. Product Frame Sudoku
12. Classic Sudoku

Results

1. Thomas Snyder (USA) - 650
2. Jan Mrozowski (Poland) - 645
3. Nikola Zivanovic (Serbia) - 640
4. Kota Morinishi (Japan) - 635
5. Michael Ley (Germany) - 630
6. Hideaki Jo (Japan) - 625
7. Minfang Lin (China) - 620
8. Rohan Rao (India) - 615
9. Fred Stalder (Switzerland) - 610
10. Sinchai R (Thailand) - 605

Best Indians

8. Rohan Rao - 615
18. Rishi Puri - 476
26. Gaurav Korde - 404
37. Sumit Bothra - 351
39. Rakesh Rai - 348

Complete Results

Before
Here's my first test. I'm going to give my best shot at ISC and I hope to retain my title :-)

After
This is satisfying! I did not solve the test under best 'physical conditions', but an 8th place overall and Indian topper with a considerable margin is something that comforts me. Nice to see Gaurav, Sumit and others back in the ring.

Sudokus were excellent. A Trio sudoku with 6 givens caught my eye, something which I failed creating sometime back. It seemed many struggled with the Product Frame which I was lucky to get through but the only barrier I faced was Outside.

Congrats to all those who qualified and hope to have an interesting finals like last year.

Logic Masters India - April 2011 Puzzle Test

2011-04-06T17:25:00.008+05:30

Logic Masters India announces the April 2011 Puzzle Test 'Twist'. It was held on 9th-10th April, 2011.
The author of the puzzles is Deb Mohanty.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is M201104P_t3istED
Forum

The puzzles that appeared in the test are:

1. Odd Skyscrapers
2. Toroidal Rectangles
3. 2-Loop Masyu
4. Light Up
5. No 3 In Minesweeper
6. 3's Fence
7. Hitori Sum
8. L&M&I
9. Double Easy As ABCD
10. Missing Breakpoints
11. No-3-Consecutive Sudoku
12. 3 Cell Arrows

Results

1. Thomas Snyder (USA) - 736.0
2. Ulrich Voigt (Germany) - 641.8
3. Hideaki Jo (Japan) - 621.0
4. Palmer Mebane (USA) - 566.0
5. Florian Kirch (Germany) - 499.8
6. Shinichi Aoki (Japan) - 479.5
7. Nikola Zivanovic (Serbia) - 473.6
8. Rohan Rao (India) - 469.1
9. Michael Ley (Germany) - 455.4
10. Kota Morinishi (Japan) - 448.0

Best Indians

8. Rohan Rao - 469.1
47. Rakesh Rai - 266.6
61. Rajesh Kumar - 241.3
80. Harmeet Singh - 173.8
82. Prasanna Seshadri - 171.8

Complete Results

Before
Every puzzle has a twist! Very interesting puzzle instructions. I'm looking forward to this test after a below par performance in Hybrids and Zoo.

The new timing structure is a nice idea. It will motivate and give a chance for more players to solve all the puzzles and complete the set. Maybe this is a start to a new trend :-)

L&M&I and Toroidal Rectangles is my pick of the set. Rectangles look scary to me, but they have very few points compared to others, so I guess they would be easy. Well, I hope so.

Good luck to all participants!

After
What a test! Absolutely fantastic set of puzzles. One of the most beautiful puzzle sets I've ever solved. The test reminded me a lot of Evergreens1 and Evergreens2, yet it had its own essence, so beautifully stuffed into the puzzles.

Skyscrapers were excellents.
Toroidal Rectangles was my weak point and it just proved to be the case. I just couldn't get through the big one, though it was my blind eye that missed an easy opening.
2-Loop Masyu was beautiful. I especially liked the small one. I started solving these using the standard rules, and when I thought I was done, I realised my solution had just one loop! I had to search for a place where I could 'open' the loop and 'close' it the other way. This puzzle made my spirits go high.
Light Up was nice. The small one used the concept of 'put as many' while the big one was a 'fit these'.
Minesweeper was average. I made a silly mistake in the small one and the big one could have definitely been better, since 40% of the grid solves without using the 'twisted' rule.
Fence and Hitori were fun.
L&M&I was my favourite puzzle of the set. The concept was nice but the execution was perfect. Both the grids were of top quality.
Double Easy as ABCD and Arrows weren't my favourite. I scraped through the Double but couldn't crack either of the Arrows.
Missing Breakpoints was undoubtedly the toughest puzzle of the set. Just 6 players solved it correctly.
No 3 Consecutive Sudoku was easy according to me. Maybe cause I'm more sudoku-friendly :-)

Congrats to Deb Mohanty for such a great set of puzzles. Congrats to Thomas for an exceptional performance! And some applause for me. My first top-10 finish in an LMI Puzzle Test! It feels nice to be at the top, at least occassionally :-) I'm dreaming of a top 3 some day...

Puzzle No.345

2011-04-05T21:39:00.000+05:30

I've never been good in creating Kakuro puzzles which reflects in my handicap in solving them too. This is an easy one that I created a while back. I'm sure you wouldn't have a tough time on this one.

PUZZLE NO.345: KAKURO

SOLUTION:

Logic Masters India - March 2011 Sudoku Test

2011-03-26T15:43:00.007+05:30

Logic Masters India announces the March Sudoku Test 'Spring'. It was held on 26th-27th March, 2011.
The author of the puzzles are Sylvain Caudmont, Timothy Doyle, Geoffroy Hermelin, Laurent Pierre, Frederic Stalder and Bastien Vial-Jaime.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is Carla20Bley3
Forum

The list of sudokus that appeared in the test are:

1. Alpha-Frame Sudoku
2. Classic Sudoku (Solving Techniques)
3. Consecutive Sudoku
4. Greater Than Killer Sudoku
5. Sudoku-Kurve
6. Arrow Sudoku
7. Sundoku
8. Extra Region Sudoku
9. Jigsaw Wordoku
10. Mixed Sudoku
11. Killer 0-8 Sudoku
12. Double Sum Sudoku

Results

1. Thomas Snyder (USA) - 954
2. Michael Ley (Germany) - 946
3. Jason Zuffranieri (USA) - 868
4. Hideaki Jo (Japan) - 846
5. Tiit Vunk (Estonia) - 841
6. Kota Morinishi (Japan) - 837
7. Nikola Zivanovic (Serbia) - 835
8. Jakub Hrazdira (Czech Republic) - 795
9. Florian Kirch (Germany) - 793
10. WaterlooMathie (Canada) - 776

Best Indians

12. Rohan Rao - 697
14. Rishi Puri - 675
18. Rakesh Rai - 575
35. Amit Sowani - 470
40. Ritesh Gupta - 440

Complete Results

Before
A very interesting set of sudokus. I liked Sundoku the best among the dozen and it will be interesting to see how it is put to good use, I'm sure the 'Francophone Authors' will live up to my expectations :-)

I've never performed well when the range of the points distribution is relatively large. Having 10 sudokus in the 0-100 point range and the other two in the 140-160 category is bound to trouble me. Some jinx I guess.

But, I'm looking forward to this test, especially since its a light weekend for me and I hope I can crack the dozen within 2hrs.

Good luck to all participants!

After
What a beautiful set of sudokus! The test was well-timed, but a little difficult for ameteur solvers. Also, no one was able to solve all sudokus correctly, which was surprised me.

Alpha Frame, Classic and Consecutive were nice and easy.
Greater than Killer was wonderfully constructed. I made a dangerous error early on while solving, 1>2>3... Was lucky to catch this goof within a minute.
Sudokukurve is one variant that I loathe. I solved it only because it was the end, and the only other variant remaining was the Killer in which I wasn't getting good progress.
Arrow and Sundoku were again nicely made, both solvable logically.
Extra Region was fantastic to solve. The use of the four-number groups (of the region and corresponding row/column) was all that was needed to crack this puzzle.
Jigsaw is again not one of favourites, especially when there are letters, but I managed to solve it without a scratch.
Mixed Sudoku was lovely. I rate it the best of this set. I just loved the way the solution went from bottom to top.
Killer 0-8 was the only puzzle I didn't solve. Didn't get any headway and it seems to be a tough one as mentioned by others in the forum.
Double Sum. This was a smile-maker and a heart-breaker. I started the test with this sudoku and solved it in about 15 minutes. I was glad with the speedy start only to be disappointed later by an error in the answer. Damn! I missed a chance to be 4th!

Overall, an amazing weekend for puzzles... great job by the authors and looking forward to the next set of sudokus as always!

Tapa Variations Contest 8

2011-03-21T12:52:00.000+05:30

Tapa Variations Contest 8 was held on 19th-20th March, 2011.
The author of the puzzles are Gulce Ozkutuk and Serkan Yurekli.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is MAK311andMAK362
Forum

Results

1. Zoltan Horvath (Hungary) - 811
2. Psyho (Poland) - 790
3. Tarotaro (Japan) - 787
4. Thomas Snyder (USA) - 762
5. Nikola Zivanovic (Serbia) - 722
6. Matej Uher (Slovakia) - 707
7. Bram de Laat (Netherlands) - 706
8. Palmer Mebane (USA) - 684
9. Ulrich Voigt (Germany) - 630
10. Michael Ley (Germany) - 613

Best Indians

39. Rohan Rao - 310
73. Rakesh Rai - 90
74. Anurag Sahay - 76
79. Tejal Phatak - 60

Complete Results

Season 2 of the Tapa Variations Contest is over. I was hoping for a top 20 overall finish, but I had a bad TVC8.
Congrats to Florian, Thomas and Psyho!

Logic Masters India - March 2011 Puzzle Test

2011-03-15T20:16:00.002+05:30

Logic Masters India announces the March Puzzle Test 'Hybrids'. It was held on 12th-13th March, 2011.
The author of the puzzles is Bram de Laat.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is P0rtm4nt34u
Forum

The list of puzzles that appeared in the test are:

1. Slitherlink
2. Seethrough
3. Worms
4. Jigsaw Sudoku
5. Skyscraper Sudoku
6. Outside Sudoku
7. Star Battle
8. Battleship
9. Myopia
10. Penta
11. Dice
12. ABC

Results

1. Hideaki Jo (Japan) - 1265
2. Palmer Mebane (USA) - 1072
3. Thomas Snyder (USA) - 1058
4. Zoltan Horvath (Hungary) - 1046
5. Michael Ley (Germany) - 1030
6. Ulrich Voigt (Germany) - 1018
7. Stefan Gasper (Slovakia) - 879
8. Nikola Zivanovic (Serbia) - 855
9. Janka1 (Czech Republic) - 844
10. Florian Kirch (Germany) - 828

Best Indians

20. Rohan Rao - 644
46. Rakesh Rai - 463
59. Neeraj Mehrotra - 374
81. Tejal Phatak - 284
82. Harmeet Singh - 284

Complete Results

Beautiful puzzles! I thoroughly enjoyed the set. I spent a shameful amount of time on Star Battle, but overall, its been a better performance than my last few LMI tests.
Congrats to Hideaki Jo, for topping the test amidst the chaos in Japan. I wish you and the country well and hope to see Japan back to its best.

UKPA Sudoku Contest 2

2011-03-15T20:01:00.000+05:30

The 2nd UKPA Sudoku Championship was held on 12th-13th March, 2011.
The author of the puzzles is Rishi Puri.

Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is SmUaDnOiKaU
Forum

Results

1. Nikola Zivanovic (Serbia) - 705
2. Thomas Snyder (USA) - 675
3. Branko Ceranic (Serbia) - 620
4. Ulrich Voigt (Germany) - 620
5. Tiit Vunk (Estonia) - 587
6. Hideaki Jo (Japan) - 584
7. Chen Cen (China) - 530
8. Caudmont (France) - 505
9. Verydao (China) - 495
10. Fred Stalder (Switzerland) - 485

Best Indians

23. Neeraj Mehrotra - 365
30. Jaipal Reddy - 330

Complete Results

I missed this contest. I've got my university exams round the corner, so had a tight weekend.
Congrats to Nikola, Thomas and Branko!

Puzzle No.344

2011-03-08T22:17:00.001+05:30

This Tapa puzzle is a good sample for using the uniqueness trick. It solves without assuming uniqueness too.

Puzzle: Tapa

PUZZLE NO.344: TAPA

SOLUTION:

Tapa Solving Techniques

Puzzle No.343

2011-03-08T22:14:00.000+05:30

Here is a Tapa puzzle using only '2's. Tried symmetry, but failed again. This is easy, just for fun :-)

Puzzle: Tapa

PUZZLE NO.343: TAPA

SOLUTION:

Tapa Solving Techniques

Puzzle No.342

2011-03-08T22:10:00.001+05:30

I was trying to create a perfectly symmetrical easy Tapa puzzle but didn't succeed. Anyway, this is the closest I got.

Puzzle: Tapa

Puzzle No.342: TAPA

SOLUTION:

Tapa Solving Techniques

Tapa Variations Contest 7

2011-03-05T12:18:00.002+05:30

Tapa Variations Contest 7 was held on 5th-6th March, 2011.
The author of the puzzles are Gulce Ozkutuk and Serkan Yurekli.

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is Lifeisshort
View Forum

Results

1. Ulrich Voigt (Germany) - 1069 (74:25)
2. Andrey Bogdanov (Russia) - 1069 (74:43)
3. Florian Kirch (Germany) - 1039 (76:50)
4. Palmer Mebane (USA) - 1035
5. Thomas Snyder (USA) - 1033
6. Psyho (Poland) - 998
7. Philipp Weiß (Germany) - 934
8. Hideaki Jo (Japan) - 911
9. Michael Ley (Germany) - 887
10. Janka1 (Czech Republic) - 885

Best Indians

22. Rohan Rao - 627
49. Rakesh Rai - 336
57. Tejal Phatak - 280
59. Harmeet Singh - 277
89. Neeraj Surana - 90

Complete Results

This was the best set out of the three TVCs. I didnt know my own variant Progressive Tapa could be used so effectively :-)
Absolutely fantastic puzzles, and great fun solving them.
Congrats to Ulrich for pipping Andrey by 18 seconds. Congrats to both of them, and Florian for solving all puzzles.
With the tournament still wide open to decide the champion, its going to be an all-out battle for the crown at TVC8!

Solving Tapa: (Elementary Beginnings)

2011-03-03T23:43:00.006+05:30

These are some good ways in starting Tapa puzzles.

CORNERS

EDGES

Other Solving Techniques

Yin-Yang Variations Contest

2011-02-24T22:14:00.004+05:30

A Yin-Yang Variations Contest was held on 26th February, 2011 from 16:00 - 18:00 GMT (21:30 - 23:30 IST).

The goal is to divide the given grid into two continuous areas - black and white. There cannot be 2x2 squares of the same colour. Black and white circles (if any) show the colour of their cell.

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is BW02diogen

All puzzles are variants of Black And White. You can solve some practise puzzles.
You can also view some Solving Techniques.

Results

1. Jana Tylova (Czech Republic) - 95
2. Masashi Sakata (Japan) - 90
3. Hideaki Jo (Japan) - 89
4. Ruben Gafencu (Romania) - 69
5. Nikola Zivanovic (Serbia) - 58
6. Bastien Vial-Jaime (France) - 57
7. Yoichi Enta (Japan) - 56
8. Andrey Lemesh (Russia) - 44
8. Kota Morinishi (Japan) - 44
10. Rohan Rao (India) - 42

Best Indians

10. Rohan Rao - 42
16. Rakesh Rai - 28
24. Swaroop Guggilam - 9
24. Tejal Phatak - 9

Complete Results

Yin-Yang or Black And White is one of my favourite puzzles. The puzzles were very well made and it was worth spending 2hrs on these puzzles, even at midnight.

Logic Masters India - February 2011 Puzzle Test

2011-02-24T22:01:00.003+05:30

Logic Masters India announces the February Puzzle Test 'Melon's Puzzle Zoo'. It was held on 26th-27th February, 2011.
The author of the puzzles is Palmer Mebane.

View Championships Page
Download Instruction Booklet
Download Puzzle Booklet
Password is 20LemONS_freAKSHOw11
View Forum

The list of puzzles that will appear in the test are:

1. Castle Wall
2. Out Of Sight
3. International Borders
4. Double Back
5. Akari EX
6. Line Nurikabe
7. Liar Slitherlink
8. Nonconsecutive Fillomino
9. Castle Wall - Masyu
10. Yajilin - Akari
11. Nurikabe - Fillomino
12. Double Back - Country Road

Results

1. Psyho (Poland) - 780
2. Nagata Yuta (Japan) - 710
3. Ulrich Voigt (Germany) - 630
4. Nikola Zivanovic (Serbia) - 620
5. Matej Uher (Slovakia) - 615
6. Zoltan Horvath (Hungary) - 590
7. Nils Miehe (Germany) - 585
8. Tarotaro (Japan) - 585
9. William Blatt (USA) - 555
10. Hideaki Jo (Japan) - 555

Best Indians

37. Rakesh Rai - 300
41. Rohan Rao - 270
80. Anurag Sahay - 90
88. Prasanna Seshadri - 55

Complete Results

Entry to the zoo was free but the wild animals in the zoo were ferocious! It was quite a tough set of puzzles, and I had a bad day.
I loved the Yajilin-Akari puzzle!

Solving Black And White: (Opposite Pairs)

2011-02-23T23:10:00.001+05:30

This is a very useful technique of solving Black And White puzzle. Take a look at the two images below.

This situation cannot occur anywhere in any Black And White puzzle! Suppose you find such a situation in a 2x2 region. When you try joining the two white circles, one black circle will be blocked from the other in either way. The same works vice-versa.

Take a look at Puzzle No.341

Try solving as much as possible without guessing.

If you do not know this technique, you may place a white circle at R1C2 and then start scratching your head. Using this technique makes this puzzle a level one puzzle :-)

Take a look at the marked 2x2 region. Since the Opposite Pairs situation cannot occur, R3C2 has to be a black circle.

Using the 2x2 constraint, R4C1 is a white circle.

Using the Edge Connection Technique, the entire edge can be made white.

Using the 2x2 constraints, some more circles can be place.

You should be able to complete it using simple logic.

Now when you look back, I'm sure you will realise how easy this puzzle is with the Opposite Pairs Technique :-)

Other Solving Techniques

Puzzle No.341

2011-02-23T22:25:00.000+05:30

Puzzle: Black And White
Author: Rohan Rao

PUZZLE NO.341: BLACK AND WHITE

SOLUTION:

Rules of 'Train'

2011-02-23T22:19:00.001+05:30

A train starts at Station No.1 and passes through the stations in numerical order. The journey cannot cross or overlap and must visit every cell exactly once.

EXAMPLE:

UNIQUE SOLUTION:

Puzzle No.340

2011-02-21T00:31:00.001+05:30

Puzzle: Tapa
Author: Rohan Rao

PUZZLE NO.340: TAPA

SOLUTION:

Puzzle No.339

2011-02-21T00:28:00.001+05:30

Puzzle: Tapa
Author: Rohan Rao

PUZZLE NO.339: TAPA

SOLUTION:

Puzzle No.338

2011-02-20T22:21:00.003+05:30

Puzzle: Tapa
Author: Rohan Rao

PUZZLE NO.338: TAPA

SOLUTION:

Tapa Variations Contest 6

2011-02-18T18:33:00.004+05:30

Tapa Variations Contest 6 was held on 19th-20th February, 2011.
The author of the puzzles are Gulce Ozkutuk and Serkan Yurekli.

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is TapaSabSeAchha
View Forum

Results

1. Thomas Snyder (USA) - 938 (60:38)
2. Philipp Weiß (Germany) - 938 (66:59)
3. Psyho (Poland) - 938 (72:44)
4. Florian Kirch (Germany) - 938 (72:46)
5. William Blatt (USA) - 917
6. Kota Morinishi (Japan) - 908
7. Nikola Zivanovic (Serbia) - 893
8. Tarotaro (Japan) - 893
9. Bram de Laat (Netherlands) - 872
10. Zoltan Horvath (Hungary) - 856

Best Indians

30. Rohan Rao - 499
51. Amit Sowani - 338
58. Rajesh Kumar - 308
66. Rakesh Rai - 278
96. Anurag Sahay - 161

Complete Results

I was hoping to improve on my TVC5 performance this time. I think I did fairly same as last time. I'm glad some of my ideas have been used as Tapa variants.
Tapa is getting better and better with every contest! Long live Tapa!

Logic Masters India - February 2011 Sudoku Test

2011-02-11T16:10:00.016+05:30

Logic Masters India announces the February Sudoku Test 'Double Delight'. It was held on 12th-13th February, 2011.
The author of the puzzles is Rishi Puri.

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is DoubledJoy
View Forum

The list of sudokus that will appear in the test are:

1. Diagonal-Nonconsecutive Sudoku
2. Jigsaw-Antiknight Sudoku
3. Diagonal-Killer Sudoku
4. Jigsaw-Killer Sudoku
5. Antiknight-Killer Sudoku
6. Nonconsecutive-Killer Sudoku
7. Jigsaw-Diagonal Sudoku
8. Disjoint-Antiknight Sudoku
9. Disjoint-Diagonal Sudoku
10. Nonconsecutive-Jigsaw Sudoku
11. Nonconsecutive-Antiknight Sudoku
12. Diagonal-Antiknight Sudoku

Results

1. WaterlooMathie (Canada) - 1035
2. Thomas Snyder (USA) - 1020
3. Jaku111 (Czech Republic) - 1002
4. Nikola Zivanovic (Serbia) - 1000
5. Chen Cen (China) - 935
6. Rohan Rao (India) - 930
7. Michael Ley (Germany) - 924
8. Takei Daisuke (Japan) - 920
9. Kota Morinishi (Japan) - 904
10. Zafer Huseyin Ergan (Turkey) - 885

Best Indians

6. Rohan Rao - 930
21. Gaurav Korde - 765
24. Jaipal Reddy - 690
33. Harmeet Singh - 575
36. Sumit Bothra - 545

Complete Results

It was a fun test. Applying two constraints to a sudoku required a lot of concentration. In the midst of the test, I kept getting confused between the variants due to repetition. I read 'nonconsecutive' and I applied antiknight! Luckily I caught myself every time I blundered and passed it with a laugh. Its been a while since I stood in the top 10 of an LMI test, so its been a good weekend for me. Congrats to WaterlooMathie for pipping the ever-topping Snyder. Maybe Snyder will be back next month with a vengeance!

Tapa Variations Contest 5

2011-02-07T22:34:00.006+05:30

The 2011 Tapa Variations Contest series has begun. This year Logic Masters India will be hosting the competitions. Tapa Variations Contest 5 was held on 5th-6th February, 2011.
The author of the puzzles are Gulce Ozkutuk and Serkan Yurekli.

View Championship Page

Download Instruction Booklet
Download Puzzle Booklet
Password is 2010MasTeRofTAPANikola

Results

1. Thomas Snyder (USA) - 841 (49:01)
2. Andrey Bogdanov (Russia) - 841 (71:27)
3. Florian Kirch (Germany) - 841 (72:32)
4. Philipp Weiß (Germany) - 812
5. Psyho (Poland) - 777
6. Nikola Zivanovic (Serbia) - 756
7. Michael Ley (Germany) - 741
8. Ulrich Voigt (Germany) - 691
9. Hideaki Jo (Japan) - 689
10. Steven Barge (UK) - 657

Best Indians

28. Rohan Rao - 435
42. Rakesh Rai - 332
62. Anurag Sahay - 242
75. Harmeet Singh - 181
103. Prasanna Seshadri - 61

Complete Results

Beautiful set of puzzles. I wasn't comfortable with Tapa Chess before the test, but I managed to solve it without much trouble. I made some silly error in Tapa Filler. I happily left Math Tapa till the end, one of my least favourite variations. Word Tapa was amazing. It took me a while to figure out the actual usage of the rules, but after that, they solved very nicely. Tapa Rotator was very simple and so was Tapa with Borders. I have never solved Double Tapa in my life (not even the example in the IB) and I surprised myself to the core by solving the Double Tapa puzzle. It was beautiful! And it felt beautiful! Tapa Connection was solvable with a little guesswork, and I just couldn't get through Tapa Possible. Maybe I missed something.
Overall, a superb Tapa variations set and a great start to this year's contests. Looking forward to some more exciting and fun-filled Tapa puzzles in the next few weeks :-)

Tapa Variations Contest 6 will be held on 19th-20th February, 2011.

Sudokucup 5

2011-02-07T21:57:00.001+05:30

The 5th Sudokucup was held on 5th-6th February, 2011.
The author of the puzzles are Slovak Sudoku Group K1Z (KLUB 162 Zelenáčov).

View Webpage

Download Instruction Booklet
Download Puzzle Booklet
Password is UA8JNNW9!?WPN5

The list of sudokus that appeared in the test are:

1. Classic Sudoku
2. External Sudoku
3. Coloured Sudoku
4. Cross Sudoku
5. Pencilmarks Sudoku
6. Coded Sudoku
7. Domino Sudoku
8. KenKen Sudoku
9. Snake Sudoku
10. Slovak Fence Sudoku
11. Romans Sudoku
12. Surprise Sudoku
13. Symmetric Odd-Even Sudoku
14. Unique Order Sums Sudoku
15. Arrow Sudoku

Results

1. Thomas Snyder (USA) - 300 (01:32)
2. Jan Novotny (Czech Republic) - 300 (01:36)
3. Hideaki Jo (Japan) - 300 (01:45)
4. Florian Kirch (Germany) - 300 (01:46)
5. Yuhei Kusui (Japan) - 300 (01:46)
6. Nikola Zivanovic (Serbia) - 300 (01:50)
7. Jason Zuffranieri (USA) - 300 (01:53)
8. William Blatt (USA) - 300 (01:56)
9. Tiit Vunk (Estonia) - 280 (01:57)
10. Kota Morinishi (Japan) - 280 (01:57)

Best Indians

34. Rohan Rao - 215
43. Rakesh Rai - 193
45. Jaipal Reddy - 191
53. Rishi Puri - 174
80. Tejal Phatak - 142

Complete Results

Nice set of sudokus. I was a little off-colour while solving, so not my best performance. Still managed to beat my other country-mates.
Congrats to Thomas for winning his 2nd Sudokucup in a row.

Solving Battleship: (Outside Sums)

2011-01-30T00:12:00.000+05:30

This is a nice technique to use while solving Battleship puzzles. You may not always find it useful directly, but it comes in handy in parts when used correctly.

Take a look at Puzzle No.12

If you cannot start this puzzle without a guess, it has to be because you are not aware of this technique :-)

Take a look at the numbers outside the grid. The total of the right-side numbers is 20. The total of the bottom numbers is also 20. The total cells occupied by ships is 20 ( 1 x 4 + 2 x 3 + 3 x 2 + 4 x 1 ). Hence, even though the blank rows/columns can be any number, they have to be zero! The cells marked in red indicate it cannot be a ship.

Using the standard rules, you should easily be able to complete the puzzle.

This technique can be used effectively when the given sums are very low or very high. If the sum of numbers is 18, the blank row/column has to have just 2 cells with ships and so on...

Other Solving Techniques

Logic Masters India - January 2011 Sudoku Test

2011-01-21T20:23:00.001+05:30

Logic Masters India announces the January 2011 Sudoku Test 'Prime Exotica'. It was held on 22nd-23rd January, 2011.
The author of the puzzles are Rakesh Rai.

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is Honorificabilitudinitatibus
View Forum

The list of sudokus that appeared in the test are:

1. DNA Sudoku
2. Kid Sudoku
3. Kombinance Sudoku
4. MultiTab Sudoku
5. Numerologidoku
6. Quad Sudoku
7. Peephole Sudoku
8. Poker Sudoku
9. Prime Number Sudoku
10. Rhombus Sudoku
11. Rossini Sudoku
12. Product Sudoku
13. Tennisdoku

Results

1. Thomas Snyder (USA) - 660
2. David McNeill (UK) - 560
3. Hideaki Jo (Japan) - 545
4. don3232 (Taiwan) - 545
5. Michael Ley (Germany) - 517
6. WaterlooMathie (Canada) - 517
7. Rishi Puri (India) - 511
8. Nikola Zivanovic (Serbia) - 489
9. Frederique Rogeaux (France) - 481
10. Jason Zuffranieri (USA) - 479

Best Indians

7. Rishi Puri - 511
19. Rohan Rao - 397
34. Amit Sowani - 309
44. Jaipal Reddy - 266
47. Sumit Bothra - 260

Complete Results

Top quality puzzles. They were complete fun to solve and the concept usage was applied very effectively. Peephole Sudoku and Rossini Sudoku were my favourite from the set. In Peephole, for a few seconds I thought it had multiple solutions, but there was a nice little corner that made it unique. That was class! The 'anti-Rossini' solved very beautifully and logically.
I'm surprised to see so few people solve Numerologidoku. I thought after getting the sums, it solved very nicely.

Good start to the new year. Hoping to see more participants and more enjoyment in the tests to come!

50 Followers

2011-01-16T22:59:00.001+05:30

I started my blog 30 months back. Yesterday, I got one of my best birthday gifts, of completing 50 followers of my blog :-)

Never did I expect so many people would follow my blog. I didn't even feel I would have 10 followers when I started! But something kept me going. Today, it feels great. It's an achievement that I am proud of.

Thank You all for your feedback, comments, participation, and anything related to this blog. I hope you find my blog useful and enjoyable (apart from some head-breaking puzzles!) and I hope to continue blogging and puzzling :-)

Domino Castle Variations Contest

2011-01-16T15:58:00.001+05:30

A Domino Castle Variations Contest was held on 15th January, 2011 from 16:30 - 18:30 GMT (22:00 - 00:00 IST).

The goal is to build correct Domino Castles in each puzzle. Domino Castle is an interconnected figure formed by complete domino set (from 1-1 to 5-5 for small puzzles, from 1-1 to 7-7 for big puzzles and from 1-1 to 4-4 for examples). Each domino of the set is used exactly once. Domino halves which share an edge should have the same digit.

Download Instruction Booklet
Download Puzzle Booklet
Password is castldo2011

Results

1. Nikola Zivanovic (Serbia) - 99
2. Shinichi Aoki (Japan) - 81
3. Takuya Sugimoto (Japan) - 69
4. Branko Ceranic (Serbia) - 63
5. Hideaki Jo (Japan) - 59
6. Jakub Hrazdira (Czech Republic) - 52
7. Masashi Sakata (Japan) - 51
8. Kota Morinishi (Japan) - 43
9. Stefano Forcolin (Italy) - 39
10. Rohan Rao (India) - 38

Best Indians

10. Rohan Rao - 38

Complete Results

Domino Castle is not one of my favourite puzzles, yet I gave it a shot, even though it being my birthday. I must admit, I enjoyed solving the set, though not very successfully :-)
I wonder why such wonderful contests have so few participants. Its just one of many question that every puzzler always seems to be having...

Logic Masters India - January 2011 Monthly Test

2011-01-06T22:46:00.004+05:30

Logic Masters India announces the January Puzzle Test 'Puzzle Jackpot'. It is the first test of 2011 and it looks to be a great one!
The author of the puzzles are Serkan Yurekli (Turkey).

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is 306090domuzcukucgeni
View Forum

The list of puzzles that will appear in the test are:

1. Skyscraper
2. Gappy Skyscraper
3. Sum Skyscraper
4. Skyscraper Either/Or
5. Domino Skyscraper

6. Snake
7. Snake Egg
8. Dotted Snake
9. Japanese Snake
10. First Seen Snake

11. Kakuro
12. Gapped Kakuro
13. Magic Summer
14. Trid
15. Orbits

16. Tapa
17. Knapp Daneben Tapa
18. Tapa ?
19. Easy As Tapa
20. Tapa Filler

21. Crisscross
22. Missing Letters
23. Scrabble
24. Jumping Crossword
25. Crisscross Crash

Results

1. Thomas Snyder (USA) - 1237.2
2. Ulrich Voigt (Germany) - 1237.2
3. Nikola Zivanovic (Serbia) - 1186.5
4. Hideaki Jo (Japan) - 1097.0
5. Florian Kirch (Germany) - 1022.2
6. Roland Voigt (Germany) - 997.2
7. Michael Ley (Germany) - 989.5
8. Branko Ceranic (Serbia) - 969.6
9. Psyho (Poland) - 963.5
10. Tomasz Strozak (Poland) - 934.8

Best Indians

35. Rohan Rao - 626.8
49. Jaipal Reddy - 503.0
50. Rakesh Rai - 499.5
51. Amit Sowani - 497.6
90. Harmeet Singh - 286

Complete Results

Very interesting concept. Points of puzzles were decided at the end of the test based on the number of people who solve each puzzle. More the people who solve a puzzle, lesser is the points. Wow!

Rules of 'Magic Summer'

2011-01-06T22:30:00.001+05:30

Fill in the grid with digits 1 to 4 such that every row and column contains each number exactly once. Numbers outside the grid indicate the sums of all numbers appearing in the corresponding row (left to right) or column (top to bottom). These numbers are separated by at least one empty cell.

EXAMPLE:

UNIQUE SOLUTION:

Solving Kakuro: (Minimax-Maximin)

2011-01-04T19:01:00.001+05:30

Most easy Kakuro puzzles have this technique used.

Take a look at Puzzle No.211

Observe the last marked row. A sum of 10 with four cells has to be 1-2-3-4 using Unique Combinations. Hence the maximum value any of those four cells can take is 4.

Now observe the marked sum of 13. The sums can be 4-9, 5-8 or 6-7. Hence, the minimum number any of those two cells can take is 4.

The minimum value and the maximum value of the marked cell is 4. Hence, it has to be 4!

This technique can even be extended to non-overlapping range of values.

Other Solving Techniques

Solving Kakuro: (Unique Combinations)

2011-01-04T18:28:00.000+05:30

This is the basic concept you need to use for solving a Kakuro. The list below gives the only possible combination of numbers for a given sum for different number of cells.

There are more such sets with higher area sizes, but these are the most commonly ones used.
The combination of numbers can occur in any order, but using these simple combinations can be very useful.

Other Solving Techniques

Solving Kakuro: (Overlapping Cells)

2011-01-03T22:30:00.000+05:30

This technique can be used effectively once you learn how to use it correctly.

Take a look at Puzzle No.9

Using this technique, you can directly find out the number in the marked cell.

The sum of the five marked cells is 12 + 21 = 33 (Using the column sums).

But, the sum of the four marked cells is 11 + 16 = 27 (Using the row sums).

Simple subtraction, and you get 33 - 27 = 6 in the marked cell.

Use this technique and you are bound to improve your solving time!

Other Solving Techniques

Indian Sudoku Championship - December 2010 Monthly Test

2010-12-24T22:30:00.004+05:30

Logic Masters India announces the December Sudoku Test 'XMas Special' which is a Classic Sudoku Relay. There were 12 Classic Sudokus. The relay indicates that there will be a set of digits that needs to be transferred from the 1st sudoku to the 2nd, from the 2nd to the 3rd and so on.
The author of the puzzles is the TTLC Team.

View Championship Page
Download Instruction Booklet
Download Puzzle Booklet
Password is 12XMas25
View Forum

Results

1. Jun Yan (China) - 1265
2. Ce Jin (China) - 1260
3. Jakub Ondrousek (Czech Republic) - 1250
4. Rishi Puri (India) - 1225
5. Don3232 (Taiwan) - 1100
6. Kota Morinishi (Japan) - 1075
7. Zafer Huseyin Ergan (Turkey) - 1075
8. RJH0723 (USA) - 1075
9. Greenhorn (Slovakia) - 1075
10. Florian Kirch (Germany) - 1075
11. Jakub Hrazdira (Czech Republic) - 1075

Best Indians

4. Rishi Puri - 1225
21. Sumit Bothra - 800
23. Gaurav Korde - 800
33. Rakesh Rai - 675
35. Akash Doulani - 575
44. Tejal Phatak - 575
46. Amit Sowani - 575

Complete Results

There were totally 146 participants.

I tested the puzzles. I completed the set in 106 minutes, so I would've probably completed 10 in 100 minutes. It was great fun organising the test offline in Mumbai. Also nice to see Sumit and Gaurav back! Looking forward to some more fun next year...

Solving Black And White: (Edge Connection)

2010-12-20T11:14:00.008+05:30

One of the fundamental techniques of solving a Black And White puzzle which most beginners would not know is this edge rule. If two circles of the same colour are placed at an edge/corner, they must be connected along an edge.

Take a look at Puzzle No.37

You may be wondering how to start this puzzle!

Have a look at the marked circles. Both are black and placed at an edge/corner.

They have to be connected along an edge, which always gives two possibilities (two directions), marked in red and blue.

The connection along the red line is not possible due to the presence of the white circle. Hence the connection has to be made along the blue line. Pretty cool, isn't it? Now the puzzle is a piece of cake.

Using the 2x2 rule, you can place the three white circles. Now observe the circle at R3C2. It has to connect with other white circles and there is only one possible way, marked in red.

Using your brains and the rules, you should easily reach this situation.

And finally, with a small ending funda, complete it.

Now, looking back, did you realise how easy this puzzle becomes when you use this edge rule? I'm sure you will find Black And White puzzles very easy to solve now :-)

Other Solving Techniques

Solving Odd-Even Sudoku: (Section Solving)

2010-12-19T00:54:00.002+05:30

The easiest method of solving an Odd-Even Sudoku is solving it in two parts. First solve the even numbers and then solve the odd numbers or vice-versa. The positions of the given odd numbers provides no clue for solving the even numbers and vice-versa, hence, it boils down to solving this sudoku in two sections.

Take a look at Puzzle No.266

Notice that every row/column/box contains four shaded cells, one for each even number.

Try solving the even numbers. Concentrate just on the even numbers and the shaded cells.

Using the basic sudoku rules, you should be able to solve it.

Now try solving the odd numbers. Concentrate just on the odd numbers and the unshaded cells.

Again using the basic sudoku rules, you should be able to solve it.

Thats it! Puzzle is solved! Use these two together and you should be able to crack any Odd-Even Sudoku without much trouble.

Other Solving Techniques

Solving Killer Sudoku: (Unique Combinations)

2010-12-18T23:48:00.002+05:30

This is the basic concept you need to use for solving a Killer Sudoku. The list below gives the only possible combination of numbers for a given sum in different sizes of area (number of cells).

Forsmarts 8th Anniversary Online Contest

2010-12-17T22:58:00.002+05:30

The 8th anniversary of the Forsmarts Online Contest was held on 18th December, 2010 at 16:00 - 18:00 GMT (21:30 - 23:30 IST).

View Championship Page

Download Instruction Booklet
Download Puzzle Booklet
Password is fs8WAtRFA

Results

1. Hideaki Jo (Japan) - 647
2. Nikola Zivanovic (Serbia) - 623
3. Jana Tylova (Czech Republic) - 593
4. Branko Ceranic (Serbia) - 538
5. Serkan Yurekli (Turkey) - 512
6. Kota Morinishi (Japan) - 500
7. Takuya Sugimoto (Japan) - 483
8. Shinichi Aoki (Japan) - 481
9. Taro Arimatsu (Japan) - 466
10. William Blatt (USA) - 455

Best Indians

24. Prasanna Seshadri (India) - 225
34. Anurag Sahay (India) - 20

Complete Results

There were totally 34 participants.

Very nice set of puzzles by Vladimir Portugalov in his typical style. Some of the puzzles were WPC 2010 type and I found Knight's Tale Sudoku the best with a beautiful logical solving path.

Puzzle No.337

2010-12-14T22:51:00.002+05:30

Puzzle: Paint
Source: Indian Puzzle Championship 2010

PUZZLE NO.337: PAINT

SOLUTION:

Indian Puzzle Championship - December 2010 Monthly Test

2010-12-11T20:07:00.002+05:30

Logic Masters India announces the December 2010 Monthly Test 'Puzzles And Chess'. It was held on 11th-12th December, 2010.
The author of the puzzles are Nikola Zivanovic.

View Webpage

Download Instruction Booklet
Download Puzzle Booklet
Password is chessMESS
View Forum

Results

1. Ulrich Voigt (Germany) - 123
2. Thomas Snyder (USA) - 111
3. Philipp Weiß (Germany) - 100
4. Hideaki Jo (Japan) - 95
5. Michael Ley (Germany) - 95
6. Psyho (Poland) - 93
7. Shinichi Aoki (Japan) - 87
8. Florian Kirch (Germany) - 84
9. Janka (Czech Republic) - 81
10. Branko Ceranic (Serbia) - 81

Best Indians

31. Rakesh Rai - 46
33. Rajesh Kumar - 43
44. Rohan Rao - 37
54. Prasanna Seshadri - 29
57. Rishi Puri - 27

Complete Results

There were totally 81 participants.

Beautiful puzzles. The usage of the chess pieces were very clinically done. The concept and implementation was brilliant.
Congrats to Ulrich, Thomas and Philipp for completing the set. Amazing performance by the Germans once again as they keep dominating the top 10.
And lastly, I wish I hadn't made those silly typos :-)

LMI tests are getting more exciting and more fun!

Puzzle No.336

2010-12-08T16:23:00.003+05:30

Puzzle: Domino Hunt
Source: Indian Puzzle Championship 2010

PUZZLE NO.336: DOMINO HUNT (0~8)

SOLUTION:

Solving Classic Sudoku: 'X-Wing'

2010-12-08T16:12:00.005+05:30

This is a very advanced sudoku solving technique. You need to have a great eye-sight to use this technique. If there is a number which can be placed only in two identical cells of different rows/columns, then that number cannot be placed in any other cell of the perpendicular columns/rows.

Take a look at this Classic Sudoku. Observe the 2nd and 6th rows.

In the 2nd row, '5' and '7' can only be placed in the cells marked in green. In the 6th row, '1' and '7' can only be placed in the cells marked in green.

The possible positions of '7' in the 2nd and 6th rows forms an x-wing and hence, '7' cannot be placed in any other cell of the perpendicular columns marked in red.

Using the '7' in R7C9, we find a unique position for '7' in the 7th box.

Other Solving Techniques

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Sudoku Online

Solving Classic Sudoku: 'Hidden Pairs/Hidden Triplets'

2010-12-08T16:11:00.001+05:30

This is just an extension of 'Naked Pairs/Naked Triplets'. If there are two (three) cells of a row/column which can take any one number of a pair (triplet) of numbers, then no other number can be placed in those two (three) cells.

Take a look at this Classic Sudoku below. Observe the 2nd and 7th columns, alongwith the 3rd row.

The 2nd column has two empty cells for '7' and '8'. The 7th column has three empty cells for '7', '8' and '9'.

All the possible candidates of every cell of the 3rd row is given. Observe R3C2 and R3C7 in the 3rd row.

'7' and '8' can be placed either in R3C2 or R3C7 in the 3rd row. Hence these two cells cannot have any other number. Hence R3C7 cannot be '9'. Using other '9's, the '9' in the 3rd box can be placed uniquely.

Other Solving Techniques

Solving Classic Sudoku: 'Naked Pairs/Naked Triplets'

2010-12-08T16:09:00.001+05:30

This is an advanced technique of solving a sudoku. It is hard to use this technique, but very useful! If there are two (three) cells of a row/column which can take any one number of a pair (triplet) of numbers, then that pair (triplet) of numbers cannot be placed in any other cell of that row/column.

Take a look at this Classic Sudoku below. Observe the 2nd, 4th and 8th columns, alongwith the 1st row.

The 2nd and 4th columns have two empty cells each for '4' and '6'. The 8th column has three empty cells for '4', '6' and '7'.

Observe R1C2, R1C4 and R1C8.

Since R1C2 and R1C4 are two cells which have to be the pair '4' and '6', they cannot be placed in any other cell of the 1st row. Hence, R1C8 cannot be '4', nor '6', and it has to be '7'.

Other Solving Techniques

Solving Classic Sudoku: 'Multiple Lines'

2010-12-08T16:08:00.003+05:30

This is just an extended version of 'Double Pairs'. Instead of two identical cells, cells belonging to two rows/columns also follows the same result.

Take a look at Puzzle No.111. Observe the '7's.

The possible cells where '7' can be placed in the 6th and 9th boxes are marked in green.

Instead of two identical pairs of cells, it can be seen that all cells belong to the 7th and 8th column. Following the same rule as the earlier one, '7' cannot be placed in any other cell of the two columns. Hence the possible cells where '7' can be placed in the 3rd box is marked in green.

Let us just place the '4' in the 1st cell to understand this concept clearly. Using the '7's, check the possible cells where '7' can be placed in the 1st and 2nd boxes.

Using the 'Double Pairs' rule, R2C9 and R3C9 are eliminated and the unique cell left in the 3rd box has to be '7'.

Other Solving Techniques

Solving Classic Sudoku: 'Two Pairs'

2010-12-08T16:07:00.001+05:30

This is a common technique used by top sudoku solvers. If you find a number occuring in the same to cells of two different adjacent boxes, then that number cannot occur in any other cell of the corresponding row/column of those two cells.

Take a look at Puzzle No.2. Try solving the centre box.

Using the earlier strategies, the centre box can be easily completed.

Observe the highlighted '4's and marked red cells which indicate cells where '4' cannot occur. Hence in the 2nd and 3rd boxes, the only possible cells where '4' can occur is marked in green.

Since '4' has to be placed in those two pairs of cells which are identical in adjacent boxes, '4' cannot be placed in any of the remaining cells of those two rows marked in red.

Observe the 1st box and using the '4' of the 1st column, there is a unique cell left where '4' can be placed.

Other Solving Techniques

Solving Classic Sudoku: 'Candidate Lines'

2010-12-08T16:01:00.002+05:30

This technique is widely used to increase the speed of solving a sudoku. When a number has to be placed in one of the two (or more) cells of a box which are in a single row/column, the number cannot be placed in any other cell of that row/column.

Take a look at Puzzle No.75. Observe the '5' in the 1st box.

The possible positions of placing a '5' in the 2nd box is marked in green.

'5' has to be placed in either R1C4 or R2C4. Either way, '5' cannot be placed in any other cell of the 4th column, marked in red.

Using the '5' of the 6th column, there is only one unique position of placing a '5' in the 8th box, marked in green.

Other Solving Techniques

Solving Classic Sudoku: 'Single Candidate'

2010-12-08T16:00:00.001+05:30

This is a very easy and straightforward method of finding a number. Select a cell (preferably with many given numbers in the corresponding row, column and box). If there is only one possible number that could be entered in the cell, it has to be that number.

Take a look at Puzzle No.104. We select R2C5 as it has many given numbers in the corresponding row, column and box.

The selected cell is marked in green.

All the numbers in the corresponding row, column and box are marked in red.

As 1, 3, 4, 5, 6, 7, 8 and 9 are present in the corresponding row/column/box of the cell, the only possible candidate for the cell is 2.

Other Solving Techniques

Logic Masters India - Screen Test 1

2010-11-28T19:42:00.010+05:30

After the success of sudoku and puzzle tests on Logic Masters India, here comes a new dimension - 'Screen Test'. Screen Tests are part of most, if not all, World Puzzle Championships. In Screen Tests, the puzzles are displayed on the screen; participants solve the puzzles by looking at the screen. Typically the answer to the screen test puzzles is a number or a letter or at max few words.
LMI Screen Test is designed based on WPC Screen Test philosophy, to make screen tests available to more puzzle solvers. The first Screen Test was held on 4th/5th/6th December, 2010.
It was organised by Deb Mohanty and me!

Download Screen Test Guide
View Screen Test Homepage
View Examples
View Forum

Results

1. Martin Merker (Germany) - 1477
2. Thomas Snyder (USA) - 1450
3. Hideaki Jo (Japan) - 1394
4. Philipp Weiß (Germany) - 1386
5. Palmer Mebane (USA) - 1376
6. William Blatt (USA) - 1363
7. Kota Morinishi (Japan) - 1352
8. Masashi Sakata (Japan) - 1350
9. Sebastian Matschke (Germany) - 1346
10. Psyho (Poland) - 1339

Best Indians

16. Keshava Murthy - 1220
23. Rajesh Kumar - 1063
26. Rishi Puri - 1038
31. Ritesh Gupta - 985
44. Prasanna Seshadri - 878

There were a total of 183 participants from 35 countries.

Complete Results

Screen Test 1 is finally over and so is one hectic weekend. It was an amazing experience! Right from building on the concept to its final implementation, it was like one joyful ride. I think organising a 30-minute Screen Test is more difficult than a 2-hour test. Trust me on this! Creating enjoyable puzzles, screen-type puzzles, solvable puzzles, with varying difficulty, deciding the timing of each puzzle, etc. required a lot of thinking. Somehow Deb and I managed it. Then came the most important part. The website. Deb designed the whole thing with me giving some small inputs. When we thought we were ready with it, it had to be tested.
Special thanks to Rajesh Kumar, Rakesh Rai, Rishi Puri, Ritesh Gupta and Tejal Phatak for removing time and solving the test beforehand and giving feedback on the interface.

I am quite satisfied with the Screen Test. I dont think there has been one earlier (WPC-style), but I may be wrong. I'm glad most of you liked the puzzles and overall enjoyed the test.
Feedback of players

About the puzzles... well... the feedback statistics say that many puzzles were solvable on screen but not all. I agree some puzzles were not solvable on screen, but we decided to keep few difficult puzzles so that even the best players get tested :-)

There were some very interesting statistics of puzzles that caught my eye.
Mazes was undoubtedly the easiest puzzle, solved correctly by maximum players with the minimum average time.
I was surprised to find Cell Sudoku solved by the least number of people. That kind of grid has only one solution. Maybe players didnt find 45 seconds enough to notice it.
Missing Words was a tight puzzle. You needed to be quick to make it within 60 seconds.
Correct XV was tough, no doubt. If you see the puzzle leisurely, you should be able to find out the errors without actually solving it.
For Mastermind, I'm sure most people would've checked which solution matches to the puzzle. It is quicker than solving the mastermind puzzle.
The last 4-5 puzzles were deliberately made a little difficult, to test players who zoomed through the first 20 puzzles.
We kept Brilliant Colours at No.25 to have a colourful and bright ending :-)

Thank You all for participating and making Screen Test 1 a big success. Please give your feedback and comments as they are most welcome.
Looking forward to seeing you all at Screen Test 2, where I hope to participate! :-)

Indian Puzzle Championship - November 2010 Monthly Test

2010-11-20T22:51:00.005+05:30

Logic Masters India announces the November monthly test 'FLIP'.
The author of the puzzles are David Millar.

Webpage

Download Instruction Booklet
Download Puzzle Booklet
Password is FLIP11PILF
Download FLIP Special Booklet

The list of puzzles that appeared in the test are:

1. Flip And Fill Sequence
2. Flip Shape Sudoku
3. Flip Strips
4. Flip Mirror Sums
5. Flip Mirror 0-2-5
6. Flip Slitherlink
7. Flip Every Second Breakpoint (by Deb Mohanty)

Results

1. Thomas Snyder (USA) - 644
2. Hideaki Jo (Japan) - 644
3. Nikola Zivanovic (Serbia) - 491
4. Jana Tylova (Czech Republic) - 459
5. Kota Morinishi (Japan) - 451
6. Michael Ley (Germany) - 443
7. Psyho (Poland) - 435
8. Shinichi Aoki (Japan) - 402
9. Stefano Forcolin (Italy) - 390
10. Rakesh Rai (India) - 370

Best Indians

10. Rakesh Rai - 370
14. Rohan Rao - 367
20. Keshava Murthy - 341
21. Rishi Puri - 338
23. Jaipal Reddy - 337

Complete Results

There were totally 98 participants.

Very nice set of puzzles. Conceptually brilliant! I liked the ESB, Slitherlink and Mirror 0-2-5. Great job David.
I felt the test could have had more puzzles to add to the positivity.
Congrats to Thomas Snyder and Hideaki Jo, who topped the test by a huge difference from others.

Puzzle No.335

2010-11-20T22:09:00.004+05:30

Puzzle: Fence
Source: Indian Puzzle Championship 2010

PUZZLE NO.335: FENCE

SOLUTION:

Puzzle No.334

2010-11-20T22:03:00.000+05:30

Puzzle: Classic Sudoku
Author: Fred Stalder

PUZZLE NO.334: CLASSIC SUDOKU

SOLUTION:

Puzzle No.333

2010-11-18T23:43:00.001+05:30

Puzzle: Sequence Sudoku
Author: Rohan Rao

PUZZLE NO.333: SEQUENCE SUDOKU

SOLUTION:

Puzzle No.332

2010-11-18T22:55:00.001+05:30

Puzzle: Irregular Sudoku
Source: Indian Puzzle Championship 2010

PUZZLE NO.332: IRREGULAR SUDOKU

SOLUTION:

Puzzle No.331

2010-11-18T22:44:00.001+05:30

Puzzle: Divisible By Three Sudoku
Source: Indian Puzzle Championship 2010

PUZZLE NO.331: DIVISIBLE BY THREE SUDOKU

SOLUTION:

Rules of 'Divisible By Three Sudoku'

2010-11-18T22:36:00.000+05:30

Place numbers in the grid such that each row, column and 3x3 box contain the numbers 1 to 9. In each 3x3 box, the number created by three horizontally or vertically adjacent digits must be divisible by 3.

EXAMPLE:

UNIQUE SOLUTION:

Puzzle No.330

2010-11-18T22:17:00.001+05:30

Puzzle: Skyscrapers
Source: Indian Puzzle Championship 2010

PUZZLE NO.330: SKYSCRAPERS (1~5)

SOLUTION:

Puzzle No.329

2010-11-18T22:12:00.001+05:30

Puzzle: Light It Up
Source: Indian Puzzle Championship 2010

PUZZLE NO.329: LIGHT IT UP

SOLUTION:

Puzzle No.328

2010-11-18T21:57:00.001+05:30

Puzzle: Arrows
Source: Indian Puzzle Championship 2010

PUZZLE NO.328: ARROWS

SOLUTION:

Rules of 'Touchy Sudoku'

2010-11-18T21:52:00.000+05:30

Place numbers in the grid such that each row, column and 3x3 box contain the numbers 1 to 9. Each digit touches, vertically or horizontally at least one consecutive digit.

EXAMPLE:

UNIQUE SOLUTION:

Puzzle No.327

2010-11-18T21:44:00.004+05:30

Puzzle: Classic Sudoku
Source: Indian Puzzle Championship 2010

PUZZLE NO.327: CLASSIC SUDOKU

SOLUTION:

Puzzle No.326

2010-11-18T20:45:00.003+05:30

Puzzle: ABC Connection
Source: Indian Puzzle Championship 2010

PUZZLE NO.326: ABC CONNECTION

SOLUTION:

Solving Classic Sudoku: 'Single Position'

2010-11-18T20:23:00.002+05:30

This is the easiest technique of finding out a number. Select a row/column/box (preferably with many given numbers) and find out the numbers remaining. Using other given numbers, try to find a unique position of one of the remaining numbers of the chosen row/column/box.

Take a look at Puzzle No.144. We select the 5th column as it has 4 given numbers. Since there is a '1' in the box above the centre box and the box below the centre box (which should be identified visually), let us try to find the position of '1' in the 5th column.

All possible positions of '1' in the 5th column are marked in green.

'1' cannot be placed in the top two and bottom two cells of the 5th column because '1' will then be repeated in a box as there is already a '1' in the two boxes.

There is only one unique position remaining for the '1' in the 5th column.

Other Solving Techniques

Solving Techniques

2010-11-18T16:57:00.018+05:30

With a lot of people asking me questions like 'How do you solve this puzzle?', 'Are there any tricks in solving this sudoku?', 'How do players solve so fast?', etc. I have decided to start sharing some solving techniques. I will post some solving techniques of common puzzles and sudokus and then move on to other more complex ones. Below is the list of solving techniques that I have posted till date.
Feel free to comment and give me feedback. If you want some solving techniques of a particular puzzle, you may ask here and I will try to post some tips :-)

Hope you like and benefit from them :-)

Sudoku Solving Techniques
Most sudokus (apart from irregular ones) are in the standard classic form, so the techniques of solving a classic sudoku apply to other sudokus with 3x3 boxes too.

Classic Sudoku
Technique 1: Single Position
Technique 2: Single Candidate
Technique 3: Candidate Lines
Technique 4: Two Pairs
Technique 5: Multiple Lines
Technique 6: Naked Pairs/Naked Triplets
Technique 7: Hidden Pairs/Hidden Triplets
Technique 8: X-Wing

Killer Sudoku
Technique 1: Unique Combinations

Odd-Even Sudoku
Technique 1: Section Solving

Puzzle Solving Techniques
Every puzzle has its own techniques but you may find some similarity between similar puzzles like Loop Puzzles, Connection puzzles, etc.

Along The Lines
Techhnique 1: Singular Cells

Battleship
Technique 1: Outside Sums

Black And White
Technique 1: Edge Connection
Technique 2: Opposite Pairs

Kakuro
Technique 1: Unique Combinations
Technique 2: Minimax-Maximin
Technique 3: Overlapping Cells

Star Battle
Solved Example 1

Tapa
Technique 1: Elementary Beginnings

I have named all the techniques, for consistency and convenience, which may differ from what you know.
Enjoy and look for more techniques coming soon!

Indian Sudoku Championship - November 2010 Monthly Test

2010-11-13T10:11:00.004+05:30

Logic Masters India announces the November Monthly Test 'Renban Groups'. It was held on 13th-14th November, 2010.
The author of the puzzles are Zafer Huseyin Ergan.

Webpage

Download Instruction Booklet
Download Puzzle Booklet
Password is 123renBAN456
Download Solution Booklet

The list of sudokus that appeared in the test are:

1. Classic Sudoku
2. Shifted Sudoku
3. Diagonal Sudoku
4. Argyle Sudoku
5. Antiknight Sudoku
6. Non-Consecutive Sudoku
7. Symmetric Unequal Sudoku
8. No Touch Sudoku
9. Chaos Sudoku
10. Diagonally Non-Consecutive Sudoku

Results

1. Rishi Puri (India) - 592
2. Fred Stalder (Switzerland) - 570
3. Jakub Hrazdira (Czech Republic) - 565
4. Rohan Rao (India) - 561
5. Jason Zuffranieri (USA) - 559
6. Hideaki Jo (Japan) - 543
7. Chen Cen (China) - 538
8. William Blatt (USA) - 529
9. Nikola Zivanovic (Serbia) - 517
10. Kota Morinishi (Japan) - 516

Top Indians

1. Rishi Puri (India) - 592
4. Rohan Rao (India) - 561
27. Rakesh Rai (India) - 409
30. Amit Sowani (India) - 393
35. Tejal Phatak (India) - 385

Complete Results

There were totally 167 participants.
Congrats to everyone!

Thanks to Zafer for this very exciting contest. The puzzles were very well-made and the use of the Renban groups were very neat and logical. I liked the 6x6 No Touch, 9x9 Shifted and Chaos the best of the lot.
Looking forward for the next contest :-)

UKPA Sudoku Contest 1

2010-11-06T17:20:00.003+05:30

The 1st UKPA Sudoku Championship was held on 6th-7th November, 2010.
The author of the puzzles are Tom Collyer.

Webpage

Download Instruction Booklet
Download Puzzle Booklet
Password is gTP97rtE1

The list of sudokus that will appear in the test are:

1. Classic Sudoku
2. Diagonal Sudoku
3. Irregular Sudoku
4. Non-Consecutive Sudoku
5. Surplus Sudoku
6. Tens Sudoku
7. No Tens Sudoku
8. No Touch Sudoku
9. Toroidal Sudoku
10. Islands Sudoku
11. Touchy Sudoku
12. Kurve Sudoku
13. Killer Sudoku
14. Arrow Sudoku

Results

1. Florian Kirch (Germany) - 256
2. Yuhei Kusui (Japan) - 242
3. Hideaki Jo (Japan) - 240
4. Alien (USA) - 220
4. Ours Brun (France) - 220
4. Chen Cen (China) - 220
4. Don3232 (Taipei) - 220
4. Jakub Ondrousek (Czech Republic) - 220
9. Ulrich Voigt (Germany) - 215
10. Nikola Zivanovic (Serbia) - 210

Indian participants

11. Rishi Puri (India) - 195
13. Rohan Rao (India) - 185
37. Tejal Phatak (India) - 120
45. Jaipal Reddy (India) - 110
45. Neeraj Mehrotra (India) - 110

Complete Results

There were totally 120 participants.
Congrats to everyone!

Very nice set of puzzles. I enjoyed solving Sudoku Islands and Surplus Sudoku. Killer was superb while the common variations were full of wonderful designs and shapes. Thanks for the puzzles and I had a good weekend :-)
Hope to see more in future.

Rules of 'No Ten Sudoku'

2010-11-05T17:57:00.000+05:30

Place numbers 1 to 9 in the grid such that each row, column and 3x3 box contains each number exactly once. The sum of the numbers in two adjacent cells cannot be ten.

EXAMPLE:

UNIQUE SOLUTION:

World Puzzle Championship 2010

2010-11-01T22:55:00.001+05:30

The 19th World Puzzle Championship was held from 24th-29th October, 2010 in Warsaw, Poland.

Official Website

Team India
Rohan Rao (Mumbai)
Rajesh Kumar (Bangalore)
Tejal Phatak (Mumbai)
Aman Pruthi (Pune)

This was my 2nd WPC and I was hoping to improve my 2008 performance (68th).
The complete IB was released quite late, after the four of us were on our flight to Poland. So it deprived us (and others) some precious practise time. The IB had some errors which could have been avoided. I was surprised when those mistakes weren't corrected even in the final print of the IB which every partipant received. That was when this 'Wavy' (As I call it, due to its unpredictable highs and lows) WPC began.

24th October
We arrived in Poland and experienced temperatures of around 8-deg C. It is quite cold for Indians which explains why Tejal wore 5 layers of clothing. After an hour's drive we reached Hotel Kuznia Napoleonska. After relaxing and taking a nap, we went for the Welcome Party. As usual, food was a big problem, especially for me, being a vegetarian. Long live bread, butter and salads!
The Welcome Party was shorter than I expected it to be, nonetheless, it was nice meeting up and chatting with the best puzzlers across the globe.

25th October
We had a city tour, went around few places with a guide and did some shopping. I was fast asleep on the way back to the hotel. Stupid jetlag.
The Q&A session after dinner was long as expected. There were quite a few doubts and incomplete instructions regarding the booklet. I guess the Polish team didn't do their homework well.

26th October
Competiton day! It started off on a high with Round 1 in which Andrey Bogdanov (Russia) was the only player to complete the round. I made an unforgivable mistake in Round 2. I forgot to solve the sudokus. It was on the last page and I completely missed it. I messed up a couple of other puzzles too resulting in a very poor score. I felt a little low after this round and was a bit off-colour throughout the remaining rounds. I managed to coverup some of those points by the end of the day. Anaconda, the deadly team round was a disaster. We had little team coordination and the fact that Aman and Tejal dislike Snake puzzles, made it even tougher for us. We were last in this round :-(
Puzzles were great and fun to solve. Thumbs up from me.
The day ended positively with Vladimir Portugalov (Belarus) and Thomas Snyder (USA) sharing their views and ideas of creating and solving some difficult puzzles. I think this was the best part of WPC 2010.

27th October
The remaining rounds went smoothly for me. No errors, but average performance. Round 10 was an interesting round where players had to make equations using numbers and signs on a ball. I did quite well in this round only to be disappointed later when the round was cancelled due to reasons I would not like to discuss. What a disappointment.
There were a couple of more mistakes in other rounds which ruined the flow of the championship.

28th October
One individual round called 'Screen Test' was supposed to take place with electronic answering machines. It was a huge mess up. Some worked, some seemed to not work, some didn't know whether it worked or no. Result: Back to paper. Waste of time, equipment, etc. It was my first screen test and it opened my eyes. The first few questions, I was too slow and by the time I realised what was happening, it was on Q.10. I put myself together and scored well in the rest of the set. My fault, but I learnt something.
Playoffs got delayed and so did lunch. Team finals were a treat to watch with the USA team racing to victory. However, a Skyscraper Sudoku is more appropriate for a WSC finals.
Individual playoffs were quite disastrous. A wrong puzzle and scrapping of a round is the last thing players want. It seems to be like the first thing that is happening. It also becomes unfair. Mehmet Murat Sevim (Turkey) and Thomas Snyder (USA) had good starts when the round was cancelled. They were unable to make it in the top 4 when the other set was used.
The finals looked more like Ulrich vs Japan rather than a 4-way battle. Three Japanese in top four. Superb performance by team Japan who also took the silver in the team finals. Many would've betted on Ulrich Voigt to add one more to his unmatchable tally and maybe few on Hideaki Jo who was consistently on the top. Ko Okamoto sprang a surprise with his speed in the semi finals and Taro Arimatsu was the cool goer. Surprise surprise! From out of nowhere, Taro Arimatsu cracked all the puzzles in the finals with consistent pace and accuracy to win WPC 2010. Ulrich finished 2nd and Hideaki 3rd.

A short trip and the farewell party wrapped up the event.

Personally, for me WPC 2010 has been a success. I stood 41st and bettered my 2008 rank. I enjoyed the trip and puzzles, though some mistakes could've been avoided.

I'm sure everyone is looking forward for the WPC/WSC combined event in Hungary next year. So am I. Hope it is better and sans errors. Looking forward to Hungary 2011!

Puzzle No.325

2010-10-22T00:07:00.003+05:30

Puzzle: Light It Up
Author: Rohan Rao

PUZZLE NO.325: LIGHT IT UP

SOLUTION:

Puzzle No.324

2010-10-22T00:04:00.002+05:30

Puzzle: Light It Up
Author: Rohan Rao

PUZZLE NO.324: LIGHT IT UP

SOLUTION:

Puzzle No.323

2010-10-22T00:01:00.001+05:30

Puzzle: Light It Up
Author: Rohan Rao

PUZZLE NO.323: LIGHT IT UP

SOLUTION:

Puzzle No.322

2010-10-21T23:57:00.001+05:30

Puzzle: Light It Up
Author: Rohan Rao

PUZZLE NO.322: LIGHT IT UP

SOLUTION:

Puzzle No.321

2010-10-20T23:44:00.001+05:30

Puzzle: Hitori
Source: Indian Puzzle Championship 2010

PUZZLE NO.321: HITORI

SOLUTION:

Puzzle No.320

2010-10-20T23:31:00.001+05:30

Puzzle: Easy As ABC
Source: Indian Puzzle Championship 2010

PUZZLE NO.320: EASY AS ABC (A~D)

SOLUTION:

Rules of 'Area Division'

2010-10-20T17:02:00.000+05:30

Divide the grid into several sub-grids such that each sub-grid has letters/numbers of the given range.

EXAMPLE: (A~D)

UNIQUE SOLUTION: