What is Sudoku?
[[File:Sudoku-by-L2G-20050714.svg|thumb|right|200px|A 9x9 sudoku puzzle...]] [[File:Sudoku-by-L2G-20050714 solution.svg|right|thumb|200px|...and the solution (the numbers in red have been added to the grid)]] {{nihongo|'''''Sudoku'''''|数独|sūdoku}} (sometimes spelled as '''Su Doku''', but also called '''''Number Place''''' or '''''Nanpure''''') is a [[puzzle]] that is very popular in [[Japan]]. It was created in [[Indianapolis]] in [[1979]] by Howard Garns and it appeared in [[Dell Magazines]] afterwards.<ref>{{cite web|url=http://onlinesudoku.hu/math-games/|title=Sudoku Variations}}</ref> Sudoku puzzles are solved by [[logic]] and no [[math]] is required. As seen on the right, it consists of a grid which is usually made up of nine [[row]]s, nine [[column]]s, and nine [[box]]es that are separated by thicker, darker lines. Some of these boxes will contain [[numeral]]s from 1 to 9. To solve the puzzle, a person must fill in all the empty squares without using the same numeral twice in each column, row, or box, and without changing the numerals that are already in the grid. These puzzles were created to be done using [[pencil]] and [[paper]], and there are many books that contain [[wikt:collection|collections]] of these puzzles with tips and [[Strategy|strategies]] for completing them. They also appear in [[newspaper]]s and [[magazine]]s: typically, a different puzzle appears every day and the solution is printed somewhere else or in the next issue. Later, small [[Handheld game console|handheld machines]] were created that [[wikt:generate|generate]] Sudoku puzzles for the user to solve. More recently, though, the game can be played on the [[Internet]] or on [[mobile app]]s. == Variations == There are many Sudoku variations that have been created since the original Sudoku's release. The grid is most often 9 by 9, but can be different sizes, though, and separated into smaller grids in different ways. For example, there is a 6 by 6 grid with dark lines between the third and fourth columns and between two pairs of r