Sudoku
Fill every row, column and 3x3 box with the digits 1–9, each exactly once. Three mistakes and the game is over.
PC: arrow keys to move, 1–9 to fill, Backspace to erase, H for a hint. Phone: tap a cell, then tap a number below.
Best time is saved in your browser. A wrong digit counts as a mistake but is not kept on the board.