Editing Sudoku (section)

== Variants ==
{{Multiple image|direction=horizontal|align=right|image1=A nonomino sudoku.svg|image2=A nonomino sudoku solution.svg|width=150|caption1=A ''[[nonomino]]'' or [[Jigsaw puzzle|jigsaw]] Sudoku, as seen in ''[[The Sunday Telegraph]]''...|caption2=...and its solution (red numbers)|alt1=A Sudoku puzzle grid with many colors, with nine rows and nine columns that intersect at square spaces. Some of the spaces are filled with a digit; others are blank spaces to be solved.|alt2=The previous puzzle, solved with digits in the blank spaces.}}

=== Variations of grid sizes or region shapes ===
Although the 9×9 grid with 3×3 regions is by far the most common, many other variations exist. Sample puzzles can be 4×4 grids with 2×2 regions; 5×5 grids with ''[[pentomino]]'' regions have been published under the name Logi-5; the [[World Puzzle Championship]] has featured a 6×6 grid with 2×3 regions and a 7×7 grid with six ''[[heptomino]]'' regions and a disjoint region. Larger grids are also possible, or different irregular shapes (under various names such as ''Suguru'', ''Tectonic'', ''Jigsaw Sudoku'' etc.). ''The Times'' offers a 12×12-grid "Dodeka Sudoku" with 12 regions of 4×3 squares. Dell Magazines regularly publishes 16×16 "Number Place Challenger" puzzles (using the numbers 1–16 or the letters A-P). Nikoli offers 25×25 "Sudoku the Giant" behemoths. A 100×100-grid puzzle dubbed Sudoku-zilla was published in 2010.<ref>{{cite book |last=Eisenhauer |first=William |title=Sudoku-zilla |year=2010 |publisher=CreateSpace |page=220 |isbn=978-1-4515-1049-2}}</ref>

==== Mini Sudoku ====

Under the name "Mini Sudoku", a 6×6 variant with 3×2 regions appears in the American newspaper ''[[USA Today]]'' and elsewhere. The object is the same as that of standard Sudoku, but the puzzle only uses the numbers 1 through 6. A similar form, for younger solvers of puzzles, called "The Junior Sudoku", has appeared in some newspapers, such as some editions of ''The Daily Mail''.

=== Imposing additional constraints ===
Another common variant is to add limits on the placement of numbers beyond the usual row, column, and box requirements. Often, the limit takes the form of an extra "dimension"; the most common is to require the numbers in the main diagonals of the grid to also be unique. The aforementioned "Number Place Challenger" puzzles are all of this variant, as are the Sudoku X puzzles in ''[[The Daily Mail]]'', which use 6×6 grids.

=== Killer sudoku ===
{{Multiple image|direction=horizontal|align=right|image1=Killersudoku color.svg|image2=Killersudoku color solution.svg|width=150|caption1=A Killer Sudoku puzzle|caption2=And its solution}}
{{Main|Killer sudoku}}

The killer sudoku variant combines elements of sudoku and [[kakuro]]. A killer sudoku puzzle is made up of 'cages', typically depicted by boxes outlined with dashes or colours. The sum of the numbers in a cage is written in the top left corner of the cage, and numbers cannot be repeated in a cage.

=== Other variants ===
Puzzles constructed from more than two grids are also common. Five 9×9 grids that overlap at the corner regions in the shape of a ''[[quincunx]]'' is known in Japan as ''Gattai'' 5 (five merged) Sudoku. In ''The Times'', ''[[The Age]]'', and ''[[The Sydney Morning Herald]]'', this form of puzzle is known as Samurai Sudoku. ''[[The Baltimore Sun]]'' and the ''[[Toronto Star]]'' publish a puzzle of this variant (titled High Five) in their Sunday edition. Often, no givens are placed in the overlapping regions. Sequential grids, as opposed to overlapping, are also published, with values in specific locations in grids needing to be transferred to others.

[[File:Comparison Sudoku.png|thumb|250px|An example of Greater Than Sudoku]]
A tabletop version of Sudoku can be played with a standard 81-card Set deck (see [[Set game]]). A three-dimensional Sudoku puzzle was published in ''[[The Daily Telegraph]]'' in May 2005. ''The Times'' also publishes a three-dimensional version under the name Tredoku. Also, a Sudoku version of the [[Rubik's Cube]] is named [[Sudoku Cube]].

Many other variants have been developed.<ref>{{cite book |last1=Snyder |first1=Thomas |last2=Huang |first2=Wei-Hwa |title=Mutant Sudoku |publisher=Puzzlewright Press |year=2009 |isbn=978-1-402765025}}</ref><ref>{{cite book |last=Conceptis |first=Puzzles |title=Amazing Sudoku Variants |publisher=Puzzlewright |year=2013 |isbn=978-1454906520 |oclc=700343731}}</ref><ref>{{cite book |last=Murali |first=A V |title=A Collection of Fascinating Games and Puzzles |publisher=CreateSpace Independent Publishing |year=2014 |isbn=978-1500216429 |oclc=1152132274}}</ref> Some are different shapes in the arrangement of overlapping 9×9 grids, such as butterfly, windmill, or flower.<ref name="ja1">{{cite web |url=http://www.janko.at/Raetsel/Zahlenraetsel.htm |title=Zahlenraetsel |website=janko.at}}</ref> Others vary the logic for solving the grid. One of these is "Greater Than Sudoku". In this, a 3×3 grid of the Sudoku is given with 12 symbols of Greater Than (>) or Less Than (<) on the common line of the two adjacent numbers.<ref name="Garns"/> Another variant on the logic of the solution is "Clueless Sudoku", in which nine 9×9 Sudoku grids are each placed in a 3×3 array. The center cell in each 3×3 grid of all nine puzzles is left blank and forms a tenth Sudoku puzzle without any cell completed; hence, "clueless".<ref name="ja1"/> Examples and other variants can be found in the [[Glossary of Sudoku]].