Sudoku rules
Grid
Sudoku is played on a 9×9 grid, subdivided into nine 3×3 subgrids (regions or boxes).
Some cells are pre-filled with digits from 1 to 9. The remaining cells are empty.
Objective
The goal is to fill the entire grid so that:
- Each row contains each digit from 1 to 9 exactly once.
- Each column contains each digit from 1 to 9 exactly once.
- Each 3×3 subgrid contains each digit from 1 to 9 exactly once.
Additional notes
Digits may not repeat within any row, column, or subgrid.
Pre-filled cells cannot be changed.
There is no guessing required. Every puzzle has a unique solution that can be reached using logic.
Game end
The puzzle is solved when every row, column, and subgrid contains the digits 1 to 9 exactly once.