SuperLite 1500 Series - Suudoku 4 Japan

Sudoku is a logic-based, combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 sub-grids that compose the grid (also called 'boxes', 'blocks', 'regions', or 'sub-squares') contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which typically has a unique solution.