Sudoku Variations

There are numerous ways to vary the basic Sudoku format. Yet, only a few variations have developed a loyal group of supporters. Most variations are regarded as a curiosity.

Variant Types

There are many ways to vary a Sudoku. Here are only a few examples:

• Change the size (4x4, 6x6, 12x12, 16x16, 25x25)
• Add extra constraints (Sudoku-X, Windoku, Asterisk, Even-Odd, Non-Consecutive)
• Replace boxes by other shapes (Jigsaw)
• Replace givens by alternative clues (Killer, Greater Than)
• Replace digits by letters, symbols or images (Wordoku, Picture Sudoku)
• Merge several constituent puzzles (Gattai, Samurai, Clueless)
• Use non-rectangular cells (Hanidoku)

To complicate things, a puzzle maker can combine several of these alterations.

Popular Variants

These often appear in newspapers or feature in dedicated puzzle books.

Killer | Sum-Sudoku | Samunamupure

Given numbers are replaced by cages labeled with the sum of the digits inside the cage. This is by far the most popular Sudoku variation.

Jigsaw | Nonomino | Squiggly | Irregular Sudoku

3x3 boxes are replaced by regions with an irregular shape.

Sudoku-X

The 2 diagonals also require digits 1 through 9.

Windoku | Hypersudoku | NRC-Sudoku

There are 4 additional 3x3 boxes in the grid which must also contain digits 1 through 9.

Samurai | Gattai-5

A puzzle with 5 partially overlapping Sudoku grids.

Common Variants

There appear occasionally in newspapers, but have dedicated websites and appear on a regular basis in Sudoku variant books.

Clueless

A puzzle with 9 Sudoku grids where the center nonets form a 10th Sudoku grid.

Flower Sudoku

A puzzle where 4 Sudoku grids each overlap 6 boxes of a central Sudoku grid.

Hanidoku

A puzzle with hexagonal cells that must contain a consecutive series of digits.

Greater Than

A puzzle where the given digits are replaced by greater-than signs.

Non-Consecutive

A puzzle where 2 adjacent cells cannot contain consecutive digits.

Other Variants

These variants are less common.

Asterisk

An ordinary Sudoku with an extra constraint which looks like an asterisk.

Sukaku

An ordinary Sudoku, except that the starting position contains pencilmarks instead of givens.

Sumo | Gattai-13

A puzzle with 13 partially overlapping Sudoku grids.

Shaolin | Gattai-25

A puzzle with 25 partially overlapping Sudoku grids.