The rules
Fill the 9×9 grid so that every row, every column, and each of the nine 3×3 boxes contains the digits 1 through 9 exactly once. Every puzzle has one, and only one, solution — you never have to guess.
Using this board
- Click a cell, then type a number or tap the keypad below the board.
- Toggle Notes to pencil in candidate numbers instead of a final answer.
- Peers of the selected cell — its row, column, and box — get a soft highlight so scanning for conflicts is easy.
- Erase clears the selected cell; Hint reveals one correct number (limited uses per game).
- Once every cell for a number is correctly filled in, that number's keypad button dims and locks — nothing left for it to do.
- Solve a puzzle to earn sudo-coins — harder difficulties pay out more.