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World Sudoku Championship 2012

The 7th World Sudoku Championship was held from 1st-3rd October, 2012 at Kraljevica, Croatia.

Championship Page

The Indian team was selected from the Indian Sudoku Championship 2012 and I had hinted this team is probably the best four in India presently (considering Rishi is not in India).

Indian Team
Rohan Rao
Sumit Bothra
Gaurav Korde
Rakesh Rai

Prasanna Seshadri

Amit Sowani

Download WSC Instruction Booklet

The first thought on seeing the IB was "This is going to be exhausting". 7 Individual Rounds + 2 Team Rounds in a day is a bit too much in my opinion.

Regarding the rounds and the puzzles, 5 of the 7 rounds were based on some linking between the puzzles. Most of the sudokus were well-known types or minor tweaks to common variations, so not much of 'new variations' to look forward to.

I finished 12th at last year's World Sudoku Championship missing the playoffs by 2 ranks. This year, only the top 8 qualify for playoffs and that was my goal.

Another surprise was defending champion Thomas Snyder's decision to not participate in the WSC as his focus and goal was to win the WPC and thus be the first player to win the WSC as well as WPC.

Part 1: Pinnochio
It was a decent start. I could solve all but one sudoku though I had 5+ mins for the last one.

Part 2: Smurfs
This was the big round. Maximum points. Triplets of sudokus linked with a pair of common cells. It was quite messy trying to look at three grids simultaneously considering the sudokus were not on the same page. A lot of turning of pages was required. It got quite irritating after a while, but it turned out to be a good round for me.
I would have preferred to have smaller sized grids, but each triplet on one page.

Part 3: Snow White And The Seven Dwarfs
Another linked round which was not very good. 7 mini sudokus and 1 big tough sudoku. The last sudoku was worth 30 points which is quite big considering the rest and most of the scores read 60 or 90+ thus giving a large point advantage to those 4~5 players who were able to solve the big one. I went for the kill attempting the 30-pointer as soon as I figured the missing clues, but fell short on time. That also lead one of my minis to remain incomplete.

Part 4: The Muppet Show
Again, flipping of pages to identify the codes of the cartoons, and then solving the Irregular Sudokus. I thought this was a bad-themed round. There was hardly any 'solving' required to figure out the codes, it was more like just flipping through all the grids and eliminating the possibilities using standard row/column/region constraints. An average round for me.

Part 5: Professor Balthazaar
This was a good round for me even though I missed the high-pointers.

Part 6: Disneyland
I've always had one bad round at every WSC and this time it was Round 6. I kept making solving errors in one puzzle after another and this round pulled me down to 11th place.

Part 7: TNT
Even though the scores weren't out (I didn't know I was 11th before this round), I had a feeling my rank was somewhere between 8th and 15th. It was a tough chance to make it to playoffs but possible if I had an extremely good round and some of the other competitors miss out.
And it turned out to be a dream round. I finished 5th (But got time bonus of 4th place because one of the top four would've turned in incorrect solutions, I think it was Jan) and all the other results went my way.

So, I finished 8th. I made it to the playoffs. The first Indian to rank in the top 10 and the first Indian to make it to a WSC playoffs (I don't consider 2009 WSC as a valid 'playoff'). It felt great, and I was extremely happy.

The playoffs format was a one-on-one quarterfinal followed by semi-final and final. I was up against 1st-placed Kota Morinishi (Japan). The one good thing about being 8th in the playoffs is, you can't get worse! So, I had nothing to lose. The sudokus to be solved during the playoffs were to be chosen by the higher ranked player 1st and then the lower ranked player from among three pools. All the top players obviously chose from the non-Classic pools, so there was not much choice for me

1st Kota Morinishi (Japan) vs 8th Rohan Rao (India)
Mine was the first playoff. An Irregular Sudoku which Kota beat me easily followed by a Medium Classic which he beat me again. 2-0 to Kota and he qualified for the semi-final.

4th Jakub Ondrousek (Czech Republic) vs 5th Hideaki Jo (Japan)
Hideaki won the first, Jakub won the second and Hideaki convincingly won the third and advanced to the semi-final against Kota.

3rd Tiit Vunk (Estonia) vs 6th Bastien Vial-Jaime (France)
Tiit won 2-1 but it was a close fight.

2nd Jan Mrozowski (Poland) vs 7th Chen Cen (China)
Jan won easily 2-0 to setup the semi-final against Tiit.

Semi-Final 1: Kota Morinishi (Japan) vs Hideaki Jo (Japan)
An all-Japan semis which Kota sweeped.

Semi-Final 2: Jan Mrozowski (Poland) vs Tiit Vunk (Estonia)
Tiit made some silly errors and Jan outclassed him.

Final: Kota Morinishi (Japan) vs Jan Mrozowski (Poland)
A best-of-5 finals which Jan won 3-1.

Individual Results

1. Jan Mrozowski (Poland)
2. Kota Morinishi (Japan)
3. Hideaki Jo (Japan)
4. Tiit Vunk (Estonia)
5. Jakub Ondrousek (Czech Republic)
6. Bastien Vial-Jaime (France)
7. Chen Cen (China)
8. Rohan Rao (India)

Complete Results

Team Results

1. Japan
2. Czech Republic
3. China
4. Germany
5. France
6. Slovakia
7. India
8. Hungary
9. Poland
10. USA

Complete Results

Indian Results

8. Rohan Rao
32. Gaurav Korde
37. Rakesh Rai
51. Sumit Bothra

39. Prasanna Seshadri (unofficial)

It was nice meeting up with everyone again and it was a dream-come-true to make it to the playoffs. The team also performed well to get 7th which equalled our 2008's 7th rank.

The sudokus were tough, which is very evident from the scores. They were fun but could have been better at a couple of places. I am not completely in favour of the playoff format used. I would never suggest a one-on-one system when the entire time you are playing against all participants simultaneously. Solving on a board is never the same as solving on paper. It may be nice for the audience but is it really the best way for solvers? Why not have the same grids on paper and use a camera, like in WSC 2010. Most of the top solvers use a lot of pencilmarks (and guesswork at times) which is not feasible on huge flex sheets. The concept of an eraser is lost.

Congrats to Jan Mrozowski who wins his third WSC title to equal Thomas's record. Good performance by Kota Morinishi and Hideaki Jo and the Japanese team for an amazing result.

Apart from a couple of problems, the organisers were helpful and did a good job. The results and checking was done at a fairly good pace and updates were regular. Thanks to all the Croatian organisers and hope to see more of you in future (but without cartoons please!).

As for the Indian results, Gaurav and Sumit were way below par and it was disappointing to see them perform poorly. But debutant Rakesh Rai had a phenomenal result ranked 37th. Hope to see him improve in future. I really missed Rishi (I hope you read this!) this year and I hope my dream of playing with him as part of Team India comes true sooner rather than later.

I'm looking forward to WSC 2013 which will be held in Beijing, China. Hope to see the top players there and I hope to perform even better next year :-)


aliye said...

how can I get the WSC Puzzle booklet?

Anonymous said...

Fantastic show Rohan ! You make us proud.

Anonymous said...

First off, great job! Congratulations!

I've often wondered how experts solve sudokus so quickly. It'd be nice if you could elaborate on some techniques that you actually use to solve hard puzzles like the ones that appear in these championships. I haven't had much experience with solving too many sudokus by hand. My current idea of solving any hard sudoku is just to repeat the following two things repeatedly: 1. fill in obvious squares (single possibility), 2. make a guess and do a dfs with backtracking.

Is this what good human sudoku solvers do (though very quickly)?

In chess at least the way humans and computers approach the game are entirely different. So I'm just wondering what the state is in sudoku.


Indian political , Common Janta & Socail life said...

Congratulations for your success. Have you tried

This website is best for you your can sent records for puzzle and can reprisent Indina.

Rajesh Kumar said...

Hi Rohan,
Its long time you posted on your blog. Looking forward for regular updates on your blog.

Scrabble Strategy said...

This is great! What a great tournament. I play Sodoku casually but can only imagine how intense and skilled the championship contenders are!

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