Good Old Sudoku
The most popular logic puzzle in Japan. The rules are simple. Each row, column and minibox comprises the numbers 1 through 9. The solver must complete the missing numbers. Sudoku is recommended by some teachers as an exercise in logical reasoning.
suduko sudoko su do ku sodoku suduku sudoku solver suuji wa dokushin ni kagiru puzlle game play kids numeral logic region nine grid subgrid