Start with the three rules
Sudoku uses a 9×9 grid divided into nine 3×3 boxes. Every row, every column and every box must contain the digits 1 through 9 once each. The printed clues stay fixed; you can change or erase your own entries.
Solve the example in three steps
First, find the empty square at the end of the top row. That row already contains 5, 3, 4, 6, 7, 8, 9 and 1, so 2 is missing. Second, check the ninth column and the top-right 3×3 box. Neither contains a 2, so the move fits both. Third, enter 2. Checking a row answer against its column and box is a useful habit.
Move from practice to the real game
The lesson board is a small teaching example. The game itself is a generated 9×9 Sudoku. Choose a difficulty and either the shared daily challenge or a practice round. Progress resumes when you open the same puzzle at the same address in the same browser.
Which digit belongs in the empty square?
Choose a number for the final square in row 1, column 9.
| Row / Column | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 5 | 3 | 4 | 6 | 7 | 8 | 9 | 1 | — |
| 2 | 6 | 7 | 2 | 1 | 9 | 5 | 3 | 4 | 8 |
| 3 | 1 | 9 | 8 | 3 | 4 | 2 | 5 | 6 | 7 |
| 4 | 8 | 5 | 9 | 7 | 6 | 1 | 4 | 2 | 3 |
| 5 | 4 | 2 | 6 | 8 | 5 | 3 | 7 | 9 | 1 |
| 6 | 7 | 1 | 3 | 9 | 2 | 4 | 8 | 5 | 6 |
| 7 | 9 | 6 | 1 | 5 | 3 | 7 | 2 | 8 | 4 |
| 8 | 2 | 8 | 7 | 4 | 1 | 9 | 6 | 3 | 5 |
| 9 | 3 | 4 | 5 | 2 | 8 | 6 | 1 | 7 | 9 |
Open the real game
Play for free in your browser. No account or installation is needed.