Swipe horizontally inside the grid to view the full board.
Select a cell · 1–9 enter a digit · N toggles notes · Backspace/Delete erase · Arrow keys move focus
Sudoku
Fill every row, column and 3×3 box with digits 1–9 without repeating a digit. Enter a number, keep notes in an empty cell, or request a hint when you need one.
About Sudoku
Sudoku is a 9×9 number puzzle. Fill each row, column and 3×3 box with digits 1–9, without repeats within any group.
There are 18 original base puzzles, six in each clue-count tier. New Game changes the grid while keeping exactly one solution. Boards are not saved. Solving a board starts a fresh puzzle after three seconds unless you choose Stay here; Continue now skips the wait.
How to play Sudoku
- 01Complete each row, column and 3×3 box with the digits 1–9. A digit cannot repeat within any one of those groups.
- 02The three labels are based on the number of starting clues: Easy has 44, Normal has 36 and Hard has 28.
- 03Select an editable cell and enter 1–9, or use pencil notes while the cell is empty. Given clues are locked. An entered digit may conflict with another cell; conflicts are marked rather than blocked.
- 04Erase clears both a cell value and its notes. Hint fills one incorrect or empty editable cell with its solution digit; if the selected cell is already correct or is a clue, the next unfinished cell is used. Each actual hint increments the hint count.
- 05Undo restores a recent effective action, up to 256 actions. Restart returns to the same puzzle; New Game uses a new seed. The board is not saved.
Sudoku controls
- Keyboard
- Use the arrow keys to focus a cell. Press 1–9 to enter a digit, Backspace or Delete to erase, and N to toggle pencil notes in an empty cell.
- Touch
- Tap a cell to select it, then tap a digit on the number pad. On a narrow screen, scroll horizontally inside the grid to view the full 9×9 board.
- Hints and history
- Hint fills a selected incorrect or empty cell with its solution value; if the selected cell is correct or a given clue, it moves to the next unfinished cell. Undo restores up to the last 256 effective actions, including notes and hint counts.
Sudoku: levels and progress
Easy starts with 44 clues, Normal with 36 and Hard with 28.
Each tier has six original base puzzles. Solving a board starts a fresh puzzle after three seconds unless you choose Stay here; Continue now skips the wait. New Game starts a different grid; Restart returns to the same puzzle. The game does not save the board.
Sudoku tips and strategies
Check all three groups
For a selected empty cell, look at its row, column and 3×3 box. A digit already present in any of those groups cannot go there.
Keep notes current
Use pencil notes to remember possible digits in empty cells. Remove candidates when a row, column or box rules them out.
Review marked conflicts
The game allows you to enter a repeated digit and marks the conflicting cells. Use the highlights to find which row, column or box needs another look.
- For an empty cell, compare the missing digits in its row, column and 3×3 box before entering a value.
- Use pencil notes to track candidates in empty cells, then remove a note when that digit is ruled out.
- Marked conflicts show repeated digits in a row, column or box. Review the highlighted groups before continuing.
Sudoku FAQ
How do the three difficulty labels differ?
They use the number of starting clues: 44 for Easy, 36 for Normal and 28 for Hard. Fewer clues leave more cells to fill.
Does every puzzle have one solution?
The 18 original base puzzles—six in each clue-count tier—were checked to have exactly one solution. Every new grid also has exactly one solution.
What does Hint do?
Hint fills one selected incorrect or empty cell with its correct digit. If the selection is already correct or is a locked clue, it fills the next unfinished cell and adds one to the hint count.
Will my unfinished board be saved?
No. The current board is not saved. After solving it, a new puzzle starts automatically in three seconds; choose Continue now or Stay here. Restart returns to the same puzzle, while New Game starts with a new seed.
What happens when I restart?
Restart clears entries and notes and returns to the same selected puzzle. New Game uses a new seed.
Can I edit a starting clue?
No. Given clues are locked. Select an editable cell to enter or erase a digit, or to add notes while it is empty.
Does Hint always use the selected cell?
It uses the selected cell if it is empty or incorrect. If it already matches the solution or is a given clue, Hint fills the next unfinished cell instead.