How to Play Sudoku: A Beginner's Guide
Sudoku looks like a maths puzzle, but there is no arithmetic at all. It is a puzzle of logic and patience, and you can learn it in five minutes.
Quick steps
- Look at the grid: 9 rows, 9 columns and 9 boxes of 3×3 squares. Some squares already have numbers.
- Fill each empty square with a number from 1 to 9.
- Make sure every row, every column and every 3×3 box contains each number from 1 to 9 exactly once.
- Find a square where only one number can fit, or a number that fits in only one square of a row, column or box, and write it in.
- Use pencil notes for the possible numbers when it gets harder, and keep going until the grid is full.
The one rule
A Sudoku grid has 81 squares arranged in 9 rows and 9 columns, and it is divided into nine 3×3 boxes by thicker lines. The rule is simply: every row, every column and every box must contain the numbers 1 to 9, each exactly once. Some numbers are given at the start. Your job is to fill in the rest. A well-made Sudoku has exactly one correct solution, and you never need to guess.
Finding your first number
Pick a number that appears often in the starting grid, say 5. Look at one box that does not have a 5 yet. Check the rows and columns that run through that box: if a 5 already appears in a row, no other 5 can go in that row, so cross those squares out in your head. If only one square in the box is left, the 5 must go there. This is called a hidden single, and it is the most useful move in Sudoku.
The other basic move is the naked single: look at one empty square and list the numbers already used in its row, column and box. If eight different numbers are used, the ninth is the only one that fits.
Using pencil notes
On harder puzzles you will reach a point where no square has a single answer yet. Then write small notes of the possible numbers in each square. In our game, tap ✏️ Notes and then the numbers. Patterns appear: if two squares in a row can only be 3 or 7, those two numbers are taken, and you can remove 3 and 7 from the other squares of that row. Our Sudoku strategies guide explains this and more.
When you are stuck
- Go through the numbers 1 to 9 one at a time and check every box for hidden singles.
- Look at the rows, columns and boxes that are nearly full first.
- Take a break. A fresh look often shows the move straight away.
- In our game, tap 💡 Hint. It explains the next step instead of just filling in a number.
Where to start
Begin with Easy Sudoku, which only ever needs the two single moves above. If small print is a problem, try large print Sudoku or print a puzzle from our printable Sudoku page.
Frequently asked questions
Do I need to be good at maths to play Sudoku?
No. The numbers are only symbols. You could play with letters or colors. Sudoku is about logic, not arithmetic.
Can a Sudoku have more than one answer?
A proper Sudoku has exactly one solution. All puzzles on RelaxPlays are checked for this.
How long does a Sudoku take?
An Easy puzzle often takes 5 to 15 minutes, and harder ones can take much longer. There is no rush.