Sudoku Rules Explained
Sudoku is a logic puzzle played on a 9×9 grid.
Three essential rules
Fill every row, every column and every 3×3 box with the digits 1 to 9 exactly once. Given numbers cannot be changed.
- Each row contains digits 1–9 exactly once.
- Each column contains digits 1–9 exactly once.
- Each 3×3 box contains digits 1–9 exactly once.
A well-formed Sudoku never requires guessing if all necessary logical strategies are known. Very difficult puzzles may demand long reasoning chains.