Mirrored from Sudopedia, the Free Sudoku Reference Guide
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.
This page was last modified 00:30, 12 November 2007.