Sudoku Help
Each row, column, and 3x3 box must contain every digit from 1 to 9 exactly once.
How This Plays
- Choose a difficulty, then start a fresh puzzle with New.
- Tap a square, then use the keypad or number keys to enter values.
- Use the pencil button to toggle notes in empty squares.
- Use Undo to reverse your last board change.
- Check tells you whether the board is clean, incomplete, or has mistakes.
- Pause freezes the timer without changing your board.
Board Highlights
- The selected square is tinted a little darker.
- Its row, column, and 3x3 box are softly highlighted.
- Matching numbers are highlighted so scanning is easier.
- Incorrect entries show in red, and duplicate conflicts are outlined.
Keyboard
- Arrow keys move your selection.
- Number keys enter values. Delete, Backspace, or 0 clears a square.
- D cycles difficulty, N toggles notes, U undoes the last move, C checks the board, P pauses, and R starts a new puzzle.