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Sudoku Rules

Sudoku is a American logic-based placement puzzle that is now very popular around the world. It consists of a quadratic 9x9 field, divided into nine 3x3 sub grids:

			Sudoku with medium difficulty
An example Sudoku

In some of the cells numbers between one and nine are given ("clues").

The aim of the puzzle is to fill all cells so that every digit between one and nine are occurs exactly once in each row, column and 3x3 block.

Sudoku have to have a unique solution. Sometimes you find poorly crafted Sudoku with multiple solution, but that should not happen.

There are variants with larger grids (16x16 with 4x4 sub grids and even 25x25 with 5x5 sub grids), and other variants with special symmetries.

			Cells Sudoku, with 5x5 sub grids and alphabetic
			characters instead of numbers (Alphadoku)
A 25x25 Sudoku. Click on the image to see a larger version

An alphadoku solver is for example Ksudoku.


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