Sudoku

Play free Sudoku online with easy, medium, and hard puzzles. Use notes and hints to complete every row, column, and 3 × 3 box.

1 playertouch · mouse · keyboardportrait layout Offline ready

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Ready to play online or offline after the first visit

How to play Sudoku

Fill the grid so every row, column, and 3 × 3 box contains the numbers 1 through 9 exactly once.

Start with a plan

These notes cover the controls, rules, and decisions in this browser version.

Choose a difficulty, select an empty square, and enter a digit from 1 through 9.
Each row, column, and outlined 3 × 3 box must contain every digit exactly once.
Turn on notes to record several candidates in a square without committing to an answer.
Resolve all empty squares without a duplicate in any row, column, or box to complete the puzzle.

Scan for a missing digit that has only one legal square in a row, column, or box before making candidate lists everywhere.
Use notes for genuinely unresolved squares and remove candidates immediately when a neighboring digit is placed.
Compare candidates inside one box; if a digit can only occupy one row or column there, eliminate it farther along that line.
When stuck, rescan the most complete units first because fewer empty squares mean fewer possible combinations.

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