How to Play Sudoku. Rules and Basics

The rules

1. The grid. Sudoku is played on a 9×9 grid divided into nine 3×3 boxes. Some cells start with given digits. your clues. and the rest are blank.
2. The goal. Fill every empty cell with a digit from 1 to 9.
3. Row rule. Each digit from 1 to 9 must appear exactly once in every row.
4. Column rule. Each digit from 1 to 9 must appear exactly once in every column.
5. Box rule. Each digit from 1 to 9 must appear exactly once in every 3×3 box.
6. Solve with logic. Every puzzle has exactly one solution, reachable using logic alone. You should never need to guess.

How to start

Look for cells where only one digit can fit because the other eight are already used in the cell's row, column, or 3×3 box. These are called naked singles. Then scan for digits that can only go in one place in a row, column, or box. hidden singles. Easy puzzles can be fully solved with just these two techniques.

For medium and above, you'll need pencil marks and pair techniques. Read beginner strategies for a structured path.

Common beginner mistakes

• Guessing. Sudoku is always solvable with logic. If you're tempted to guess, you've missed a single somewhere. go back and scan each digit one at a time.
• Forgetting the box rule. Beginners scan rows and columns but skip the 3×3 boxes. The box constraint is just as important.
• Trying everything at once. Focus on one digit at a time, or one cell at a time. Don't try to hold the whole grid in your head.

Ready to play?