Sudoku
Fill the 9 by 9 grid so every row, column and 3 by 3 box holds the digits 1 to 9 once.
- Time
- 0:00
- Mistakes
- 0/3
- Best time
- -
Keys 1 to 9 enter a digit, Backspace erases, N toggles notes and the arrow keys move. Your unfinished puzzle and best times are saved on this device.
How to use it
- Pick a level, select a square and enter a digit with the number pad or your keyboard.
- Switch on notes to pencil in candidates, and use undo or a hint when you are stuck.
- Fill every square correctly to finish. Three wrong digits end the puzzle.
Questions
Does every puzzle have exactly one solution?
Yes. A square is only removed while the puzzle still has a single solution, so you never need to guess. Hard and expert puzzles also need techniques beyond simple singles.
What counts as a mistake?
Entering a digit that differs from the solution. Pencil notes, erasing and hints do not count, and three mistakes end the puzzle.
Do hints affect my best time?
Yes. A solved puzzle that used a hint is not saved as a best time, so the records stay honest.
What happens if I close the page?
The unfinished puzzle, notes and timer are saved in this browser on this device and resume when you come back. Nothing is sent anywhere.
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