Blue Sudoku

Blue Sudoku is a quiet place to solve puzzles.

No account, no sign-up, no daily streak nagging you to come back. Open it, pick a difficulty, and play. Your progress is saved automatically, so you can put it down mid-puzzle and pick it up days later exactly where you left it.

FIVE DIFFICULTIES, EARNED IN ORDER
Easy and Medium are open from the start. Play Medium five times and Hard unlocks, then Expert, then Chaos. Each level is a real step up, and reaching the next one means something because you got there by playing.

BUILT FOR LONG SESSIONS
• Pencil marks for the possibilities you are still weighing
• Highlighting for the row, column and box you are working in
• Matching digits lit up across the grid
• Undo, erase, and a hint when a puzzle stops moving
• A timer you can hide entirely if it stresses you out

FIVE THEMES
Light, Classic black and white, Dark, and two pastels — Lavender and Peach. Correct and incorrect entries stay clearly distinguishable in every one of them, which is not a given and took some care to get right.

TRACK YOUR PROGRESS
Per difficulty: games played and won, win rate, flawless wins, best and average time, current and best streak. All of it stays on your device.

ELEVEN LANGUAGES
English, Turkish, German, French, Spanish, Italian, Brazilian Portuguese, Japanese, Arabic, Urdu and Persian.

EVERY PUZZLE IS SOLVABLE BY LOGIC
Puzzles are generated with a single guaranteed solution and graded by the techniques they actually require. You will never need to guess.

PLAYS OFFLINE
The puzzles are generated on your device, so the game works on a plane, on the underground, or anywhere with no signal. Only the ads need a connection.

A NOTE ON ADS
The game is free and supported by ads: a banner while you play, and an occasional full-screen ad between games. Video ads are always optional — you watch one only if you choose to trade it for extra hints, and declining costs you nothing but the hint.