A quiet moment with a fresh 9×9 number puzzle. Use pencil notes, hints and undo to find the one correct solution.
No installationDesktop · mobile
ReadyTime played 00:00
Preparing your game…
Take a break. Resume when you are ready.
Select a cell, then use the number pad or keys 1–9. N toggles notes; Backspace erases. Red cells show duplicates in a row, column or box.
Play stays in this browser. A new game, page reload or language change resets progress. Scores and input are not sent to a server.
How to play
Select an empty cell and enter a number from 1 to 9. The darker given numbers cannot be changed.
Fill every row, column and outlined 3×3 box without repeating a number.
Keep candidates in Notes and use a Hint when you need help. Finish by filling every cell correctly.
Good to know
Each puzzle is generated in this browser and checked for a unique solution. Difficulty is based on the number of clues, rather than a guaranteed solving technique.
Red cells highlight duplicates among your current entries. An entry without a conflict can still be wrong. Undo does not reduce the number of hints used.
Play without signing in or submitting a score.
PLAY & LEARN
Sudoku · Rules and strategy
Sudoku is about eliminating candidates rather than doing arithmetic. Fill a 9×9 board while meeting row, column and box constraints at the same time. Choose a difficulty and use notes, undo and hints to practice a deliberate solving process.
Rules and controls
Each row, column and 3×3 box must contain 1 through 9 once each. Select an empty cell and use the number pad or keyboard. Given clues cannot be changed. Notes record candidates and do not count as completed answers.
A useful first strategy
Start with rows or boxes that already contain many digits. Alternate between cells with only one possible value and digits with only one possible position in a box. These checks reduce the need to guess.
Worked example
If a row contains 1, 2, 3, 4, 5, 6, 7 and 8 with one empty cell, the missing digit is 9. With several empty cells, compare their columns and 3×3 boxes too.
Frequently asked questions
How should I use hints?
Hints help you move forward and their usage is counted. Try noting candidates first, then use a hint at a genuine sticking point to learn from the next step.
Does sharing send my current game?
Share sends the game address in the current language. It does not copy your board, nickname or score.