Sudoku

About Sudoku

Fill a 9×9 grid so every row, column, and 3×3 box contains the digits 1–9. One of the most popular logic puzzles in the world.

How to Play Sudoku

Click an empty cell and type a number 1–9. Every row, every column, and every 3×3 sub-grid must contain each digit exactly once. Use the given clues to deduce what goes where. No guessing required!

History of Sudoku

Sudoku's modern form was designed by American architect Howard Garns in 1979 under the name "Number Place" and published in Dell Magazines. The puzzle was rediscovered by Japanese publisher Nikoli in 1984, which gave it the name "Sudoku" — short for a Japanese phrase meaning "the digits must remain single." It became a global craze in 2004 when The Times of London began publishing it, triggering a worldwide puzzle explosion in newspapers everywhere. Despite the numbers, Sudoku requires no arithmetic — only pure logic. Play Sudoku free online here with five difficulty levels, from beginner to expert, all in your browser with no download required.

Tips & Tricks

• 1.Start with the number that appears most frequently on the board — it has the fewest empty cells to fill.
• 2.Use the "cross-hatching" technique: draw imaginary lines through rows and columns where a number already exists to find where it must go.
• 3.If a number can only go in one cell within a row, column, or box — it must go there, even if other constraints are not yet solved.
• 4.Use pencil marks (notes mode) to track candidate numbers in cells and eliminate them as you solve neighboring cells.
• 5.Never guess — every Sudoku puzzle in this game has exactly one solution reachable through pure logic.