How to play Sudoku

Start with one certain move. These small examples explain the rules and a simple way to begin a Sudoku puzzle.

Play Sudoku

1. Find the missing number in a row

Every row contains 1–9 exactly once. This example already has eight numbers. Which number is missing?

12345678?
Reveal the row answer

9. The digits 1–8 are already present, so 9 is the only missing digit. On a real board, check the column and box too before placing it.

2. Apply the same rule to a box

A Sudoku board has nine 3 × 3 boxes. Every box also needs each digit from 1 to 9 once. What belongs in the highlighted square?

1234567?9
Reveal the box answer

8. Every other digit is already in this box. The same missing-number check works for columns.

3. Use notes when more than one number fits

If your checks leave two possibilities, such as 2 and 6, keep both as notes. A note is a possibility, not an answer. Wait for another move to rule one out.

In ELAVAS IQ, select an empty square, turn Notes on and choose the candidate digits. Turn Notes off before entering your final answer.

4. Check all three directions

  1. Look at the square’s row. Which digits are already there?
  2. Check its column and its 3 × 3 box.
  3. Remove those digits from your possibilities. If exactly one remains, you have a certain move.

A square can also be forced when it is the only place a particular digit can go in a row, column or box. Avoid guessing if you can still find a logical move elsewhere.

Try an easy puzzle

Choose Easy to begin. Select a square, then use the number row below the board. Undo reverses a move, Hint can help when you are stuck, and three mistakes end the attempt. Undo does not restore a mistake.

Your unfinished puzzle saves in this browser. Opening this guide does not change it.