How to Play Sudoku
Sudoku is a logic puzzle on a 9 × 9 grid. Some cells start with digits; you fill in the rest.
The rule
The grid has 9 rows, 9 columns and nine 3 × 3 boxes. Fill every empty cell with a digit from 1 to 9 so that:
- every row contains 1 to 9 exactly once,
- every column contains 1 to 9 exactly once,
- every box contains 1 to 9 exactly once.
That's all. The given digits can't be changed, and every puzzle has exactly one solution.
Difficulty
| Level | Given digits | What it takes |
|---|---|---|
| Easy | about 38 | Finding the only cell a digit can go in |
| Medium | about 30 | The same, with fewer clues to start from |
| Hard | about 24 | Notes and pairs (see the strategy guide) |
Playing on kawu
- Click a cell, then a digit on the pad (or type 1–9). Arrow keys move; Backspace erases.
- Notes: switch on notes, or hold Shift while typing, to pencil in candidates. Filling a digit removes it from the notes in its row, column and box.
- Repeated digits in a row, column or box are underlined in red. In the settings you can also show digits that don't match the solution.
- Hint points to the easiest next cell, or fixes a wrong digit. Undo takes back as many steps as you like.
- Daily puzzle: everyone gets the same medium puzzle each day. Compare your time with friends.
Play Sudoku now or try today's puzzle.
Frequently asked questions
Do you need maths to play Sudoku?
No. The digits are just symbols; you never add them up. Sudoku is pure logic.
Can a Sudoku have more than one solution?
A proper Sudoku has exactly one. Every kawu puzzle is checked to have a single solution.
Do I ever have to guess?
Not on kawu. Easy and medium puzzles can be solved by finding the one place a digit can go; hard puzzles need a few more techniques but still no guessing.
Last updated 2026-10-18