Rules of 'Heyawake'

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:

Rules of 'Train'

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:

Rules of 'Magic Summer'

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:

Rules of 'Divisible By Three Sudoku'

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:

Rules of 'Touchy Sudoku'

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:

Rules of 'No Ten Sudoku'

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:

Rules of 'Area Division'

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

EXAMPLE: (A~D)


UNIQUE SOLUTION:

Rules of 'Anglers'

The grid represents a lake and the numbers on the periphery represent anglers (fishermen). The fishes shown in the lake are such that every angler gets exactly one fish. The numbers indicate the length of the fishlines which are composed of horizontal and vertical line segments. Draw the fishlines starting from grid border such that no two of them cross or overlap each other.

EXAMPLE:



UNIQUE SOLUTION:

Rules of 'Loop'

Draw a single closed loop that visits all white cells of the grid exactly once. The loop is made up of horizontal and vertical line segments and cannot intersect/overlap itself.

EXAMPLE:


SOLUTION:

Rules of 'No Four In A Row'

Fill in the grid with 'X' or 'O' such that four consecutive 'X's and 'O's do not appear horizontally, vertically or diagonally.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Futoshiki'

Place numbers of the given range in the grid such that every row and column contains each number exactly once. Inequality constraints must be satisfied. The open end of the sign denotes the greater number.

EXAMPLE: (1~4)


UNIQUE SOLUTION:

Rules of 'Fillomino'

Divide the grid into polyminoes such that each given number 'N' is part of an N-polymino. No two polyminoes of the same size are orthogonally adjacent.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Light It Up'

Place light bulbs in some white cells in the grid so that every white cell in the grid is lit. A cell is illuminated by a light bulb if they are in the same row or column, and if there are no black cells between them. No light bulb may illuminate another light bulb. A number in a black cell indicates the number of light bulbs sharing an edge with that cell.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Hashi'

Each circle in the grid represents an island. Draw horizontal/vertical bridges between islands such that all islands are connected to each other. Bridges cannot cross each other. The number inside each circle represents the number of bridges connected to it. No more than 2 direct bridges exist between two islands.

EXAMPLE:



UNIQUE SOLUTION:

Rules of 'H2O'

There are a number of water (H2O) molecules in the grid, each composed of two Hydrogen(H) atoms and one Oxygen(O) atom. Atoms in a molecule connect each other either in a straight line or in a 90-deg angle. Locate the Oxygen atoms, which do not touch each other, not even diagonally.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Quadro Sudoku'

Place numbers in the grid such that every row, column and 3x3 box contain the numbers 1 to 9. No 2x2 region can contain all odd or all even numbers.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Queen Sudoku'

Place numbers in the grid such that every row, column and 3x3 box contain the numbers 1 to 9. One number (usually '9') in the grid is a chess Queen. Two Queens cannot be placed along the same row, column or diagonal of any length.

EXAMPLE: (9)


UNIQUE SOLUTION:

Rules of 'Average Sudoku'

Place numbers in the grid such that every row, column and 3x3 box contain the numbers 1 to 9. If the number in a cell equals the average of its two horizontal(vertical) neighbours then the cell is marked with a horizontal(vertical) line.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Descriptive Pairs Sudoku'

Place numbers in the grid such that each row, column and 3x3 box contain the numbers 1 to 9. Each pair of digits A and B on the outside means that at least one of the following are true in the row/column:
a) There is a digit A in the Bth cell
from the edge.
b) There is a digit B in the Ath cell
from the edge.

EXAMPLE:


UNIQUE SOLUTION:

Rules of 'Mirror Sudoku'

Place numbers in the grid such that each row, column and 3x3 box contain the numbers 1 to 9. The 1st and 9th boxes, and the 3rd and 7th boxes are mirror images of each other.

EXAMPLE:


UNIQUE SOLUTION: