Quick guide
How to play Sudoku
Fill every empty square with a number from 1 to 9. Each row, column, and outlined 3 × 3 box must contain every number exactly once.
Use the tools
- Notes adds small candidate numbers instead of a final answer.
- Erase clears your selected square.
- Hint fills the selected empty square for you.
Good first move: Scan for a row, column, or box that is missing only one number.
Keyboard: arrows move · 1–9 enter · N toggles notes · Backspace erases · H gives a hint