A LITTLE FOCUS. A FRESH START.
Play Even/Odd Sudoku
Play Even/Odd Sudoku free online. Circles mark odd numbers and squares mark even numbers, with five difficulties, notes, and hints.
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The game loads here. Choose a difficulty to start or resume a puzzle.
LEARN THE TWIST
How to play Even/Odd Sudoku
Parity symbols restrict individual cells, unlike the pair relationships in Kropki. Unmarked cells can contain either odd or even digits.
The rules
Fill each row, column, and 3×3 box with 1–9, without repeats. A shaded circle marks an odd digit; a shaded square marks an even digit. Unmarked cells can contain either.
A useful first move
Filter pencil marks by parity before checking neighboring cells. Marked cells can reserve the last available positions for an odd or even digit in a box.
A shaded circle permits 1, 3, 5, 7, or 9. A shaded square permits 2, 4, 6, or 8. If a square has candidates 3 and 6 from its row and column, it must be 6.
Controls, difficulty, and saved games
Choose Beginner, Easy, Medium, Hard, or Expert above. Select an empty cell, then tap a number or use your keyboard. Notes let you pencil in candidates; three hints are available. Three mistakes end the puzzle.
Every mode and difficulty keeps a separate save in this browser. You can switch puzzles and return to your place. Clearing site data removes these saves; they do not sync with another device or the iPhone app. Settings include night mode and optional automatic cell advancement.
Correct entries earn points. High scores are stored by mode and difficulty and update only when beaten; completed-puzzle count and day streak are shared.
FIFTEEN WAYS TO PLAY
Explore all Sudoku modes
A familiar grid, a different kind of logic. Every mode is free to play in your browser.