How to Play Sudoku for Beginners: Rules and 5 Techniques
Sudoku is a logic puzzle, not a maths puzzle. You never add numbers: you only decide where each digit can and cannot go.
The rules
Fill the 9×9 grid so that every row, every column and every 3×3 box contains the digits 1 to 9 exactly once. Some cells start filled. These are the clues.
Five techniques, in the order to use them
1. Scanning
Pick a digit, say 5. Find every 5 on the grid. Each one rules out its row, column and box for another 5. Often a box has only one cell left where 5 can go, and you have a solved cell.
2. Naked single (one candidate left)
Look at a cell and the numbers already in its row, column and box. If only one digit remains possible, that is the answer.
3. Hidden single
A digit may have many candidates in a cell but only one cell in a row, column or box where it can go. That cell must hold it, even if the cell has other candidates.
4. Pencil notes
For medium puzzles, write all the possible digits in each cell. The notes make the next two techniques possible. A good Sudoku app removes a digit from the notes of its row, column and box automatically when you place it.
5. Naked pairs
If two cells in the same row, column or box both have only the same two candidates, say 3 and 7, those two digits belong in those two cells. Remove 3 and 7 from every other cell in that group.
A step by step method
- Scan for easy singles until you stop finding any.
- Fill in the pencil notes.
- Look for cells with only one candidate and for hidden singles.
- Look for pairs and remove candidates.
- Go back to scanning, because every new digit opens more.
Do not guess
A proper Sudoku has exactly one solution and can always be solved by logic. If you feel you must guess, you have missed a step. Look at the notes again, or use a hint to learn what you missed.
The free Sudoku on Cheettukali has Easy, Medium and Hard puzzles, notes, undo and hints, and each puzzle is checked to have exactly one solution.
🃏 Try it now: play Sudoku free in your browser, no download, no money.
FAQ
Do you need to be good at maths for Sudoku?
No. The numbers are only symbols, and you never add or multiply.
Is it OK to guess in Sudoku?
A well-made puzzle can always be solved by logic, so guessing is not needed. If you are stuck, use notes or a hint.
What is the best way to start a Sudoku?
Scan for digits that appear many times, and find the cells where they can only go in one place.
What difficulty should a beginner choose?
Easy. About 40 clues are given, and singles are enough to finish it.