How to play Sudoku
Fill every row, column, and 3×3 box with the numbers 1–9. Each number can appear only once per row, once per column, and once per 3×3 box. The pre-filled numbers are your starting clues — don't change them.
Click Check to see if your current entries are correct. Click Hint if you're stuck. Click New to get a fresh puzzle of the same difficulty.
Sudoku solving tips
- →Start with easy cells — look for rows, columns, or boxes that already have 7 or 8 numbers filled in.
- →Eliminate candidates — for each empty cell, list which numbers are still possible based on its row, column, and box.
- →Naked singles — if only one number is possible in a cell, that's the answer.
- →Hidden singles — if a number can only go in one cell within a row, column, or box, place it there.