Choose a difficulty and start a puzzle.
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Play Sudoku
Select a difficulty. The slider matches the original java applet: more givens is simpler; fewer givens is harder.
Play Sudoku Online
The puzzle is a 9×9 grid divided into 3×3 regions. Fill each blank square with a number from 1 to 9 so each row, column, and region contains every number once.
Click a square to select it. A selected blank square shows a pencil-mark grid; tap a small number to toggle a pencil mark, or use the number buttons below the board to enter your answer. Keyboard entry, Delete/Backspace, and arrow-key movement are supported.
Helpful controls include Mark hints, Auto-unmark to remove pencil marks after correct answers, Mistake alert, restart, undo, sounds, and the five-mistake limit.