Sudoku description

Sudoku is a logic puzzle game with numbers.

The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids (blocks) that compose the grid contains all of the digits from 1 to 9. At the beginning each puzzle is filled with some initial digits and a player is required to fill in the missing digits according to the rules.