SUDOKU

How to play

Fill the 9×9 grid so every row, column and 3×3 box contains the digits 1 through 9 exactly once. Tap or click a cell to select it, then enter a number with the on-screen keypad or your keyboard — arrow keys move the selection too. Toggle Notes mode to pencil in small candidate digits before committing to an answer. A digit turns red the instant it clashes with the same number in its row, column or box, so mistakes are always visible. Pick a difficulty, race the clock, and try to beat your best time.