How to play Sudoku

Fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids (boxes) contain all of the digits from 1 to 9.

1. I.Row rule: Each row must contain digits 1-9 with no repetition.
2. II.Column rule: Each column must contain digits 1-9 with no repetition.
3. III.Box rule: Each of the nine 3×3 boxes must contain digits 1-9 with no repetition.

• Click any empty cell to select it. The cell turns blue.
• Type a number 1-9 (or click the buttons below the board) to fill it.
• If the number conflicts with another in the same row, column, or box, it will turn red.
• Use Backspace to clear a cell, or the ⌫ button.
• Use Ctrl + Z (or the ↶ button) to undo.
• Use arrow keys (↑↓←→) to move between cells.
• Press N for a new game, T to toggle theme, L to toggle language.
• Your progress saves automatically. Refresh anytime to resume.

• Start with rows, columns, or boxes that already have many numbers filled in. It's easier to spot the missing digit.
• Look for cells where only one digit is possible. For example, if a row has digits 1-8, the missing cell must be 9.
• Use the error highlighting: red cells mean a conflict, so undo or try a different number.
• Our daily puzzle is Medium difficulty with about 33 clues given. There are easier (Easy) and harder (Hard) archives available too.