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Sudoku is a number puzzle where each row, column, and 3x3 box must contain the digits 1 through 9 without repetition.

About Sudoku

Sudoku is a modern number-placement puzzle based on Latin-square logic. Although it became globally famous through newspapers, its appeal comes from pure deduction rather than arithmetic.

Select an empty cell, choose a number, and use the check and hint controls when you need help.

Origin and background

Sudoku became popular because it offers a pure logic challenge with almost no theme or story. The numbers are symbols; the puzzle is really about constraints.

A good Sudoku puzzle can be solved step by step. Guessing may work sometimes, but the satisfying path is to find the reason each number belongs in a specific cell.

How to play

Select an empty cell and choose a number. Check the row, column, and 3x3 box before placing it. If a number already appears in any of those areas, it cannot be placed there.

When stuck, scan for the most complete row or box. Fewer empty cells usually means fewer possible candidates.

Rules

Fill every empty cell with a number from 1 to 9.
Each row must contain every number once.
Each column and 3x3 box follows the same rule.

Beginner tips

Start with rows or boxes that have many numbers.
Use pencil marks for uncertain cells.
Look for single-candidate cells first.

Common mistakes

Guessing too early instead of checking candidates.
Looking only at rows and forgetting the 3x3 boxes.
Failing to revisit a cell after new numbers are placed nearby.

Why it is still fun

Sudoku is still popular because each solved cell gives a small moment of progress. The rules are fixed, but every puzzle creates a different chain of deductions.

It is a strong choice for players who want a quiet puzzle that rewards careful attention.

Play Sudoku

Open the playable browser version, then return to this guide whenever you want to review the rules or beginner strategy.

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Sudoku FAQ

Do I need math to play Sudoku?

No. Sudoku uses numbers, but the puzzle is about logic and placement.

Can a number repeat in a row?

No. Each row, column, and 3x3 box must contain 1 through 9 once.

What should beginners look for first?

Start with rows or boxes that already have many numbers filled in.