How to play Sudoku: rules for beginners

Sudoku is a number puzzle played on a grid of 81 squares. You do not need to be good at maths. No adding or subtracting is involved, because the numbers are only symbols. What you need is patience and a little logic.

The goal

Fill every empty square with a number from 1 to 9 so that the whole grid is complete and correct.

The three rules

Rows: each row (left to right) must contain the numbers 1 to 9, with no number repeated.
Columns: each column (top to bottom) must also contain 1 to 9 exactly once.
Boxes: the grid is divided into nine smaller 3×3 boxes, marked by thicker lines. Each box must contain 1 to 9 exactly once too.

Some squares already have numbers. These are the clues, and they cannot be changed. A good Sudoku puzzle has exactly one correct solution.

Solving your first puzzle

Start with an easy puzzle and follow these steps.

Pick a number that already appears several times, such as 5. Look at where the 5s are.
Pick a box that has no 5 yet. The 5s in the neighbouring rows and columns rule out some of its squares.
If only one square is left in that box, the 5 must go there. This is called a "single".
Repeat with other numbers and boxes. Each number you place gives you new clues.
Look at the empty squares in a row, column or box that is almost full. If only one number is missing, it goes in the last square.

Tip: never guess. If you are unsure, look for another square where the answer is certain. A correct Sudoku can always be solved by logic.

Using pencil marks

When no square has an obvious answer, write small "pencil marks" in the empty squares, listing every number that could still fit. As you place numbers, cross them out of the marks nearby. Soon a square will have only one possibility left. In our game, turn on Notes to do this.

Difficulty levels

Easy puzzles have many clues and can be solved with singles alone. Medium puzzles need pencil marks. Hard puzzles have fewer clues and need advanced techniques, which you can read about in our Sudoku tips.

Common mistakes

Guessing, then finding a conflict many moves later.
Forgetting to check the box as well as the row and column.
Concentrating on one area. If you are stuck, switch to a different part of the grid.

Ready to try? Pick Easy in the game and use the daily puzzle to build a habit.

Play Sudoku now