Eighty-one cells. Nine rows. Nine columns. Nine 3x3 boxes. Each needs the numbers 1 through 9 exactly once. No guessing allowed.
What is Sudoku?
Sudoku is a logic-based number puzzle where you fill a 9x9 grid so each row, column, and 3x3 box contains every digit from 1-9 without repeats. It’s a Puzzle game that tests deduction and pattern recognition.
With difficulty levels from easy to expert, Sudoku works for both beginners learning the basics and experienced solvers looking for a challenge. Every puzzle is solvable through logic alone - no luck required.
How to Play Sudoku
Pick a difficulty level. Easier grids have more starting numbers. Expert puzzles give you minimal clues and require advanced logic to solve.
Click any empty cell and enter a number. The game validates every placement against row, column, and box rules. Use the pencil tool to jot down candidate numbers in cells before committing. A number counter shows how many of each digit remain, letting you track which numbers are almost placed.
Strategy tip: start with rows, columns, or boxes that already have the most filled numbers. The fewer unknowns, the easier the deduction. Work in waves - obvious placements first, then elimination, then advanced patterns like hidden pairs or X-wing.
Tips and Tricks for Sudoku
Work the most populated areas first Boxes and rows with more given numbers are the fastest to complete.
Pencil candidates before placing Marking all possible numbers for each cell reveals hidden patterns.
Read the counter It tells you exactly how many of each number remain - use it to spot what’s almost done.
Game Controls
| Action | Controls |
|---|---|
| Select cell | Click |
| Place number | Click number button |
Frequently Asked Questions
Is Sudoku free to play online?
Yes. Sudoku runs in your browser for free with no download.
What difficulty levels does Sudoku offer?
Easy, medium, hard, and expert. The number of given cells varies per level.
Can Sudoku be played without guessing?
Yes. Every puzzle is designed to be solvable through pure logical deduction.
Does Sudoku have a timer?
Yes. The built-in timer lets you track your solve speed and compete against your personal best.