Tidoku: Daily & Killer Sudoku

About Tidoku

Tidoku is the sudoku that notices your clever moves. Find a Naked Pair or an X-Wing yourself and it names the technique, then shows you what to learn next. Every puzzle solves by logic, no guessing. Killer Sudoku, a daily sudoku, and it plays offline.

Spotted: a sudoku that sees how you solve

• Place a digit no single could give you, with no hint open, and Tidoku names the technique you just used: Spotted! A glass bell rings and a short voice line in English cheers.
• Spot a technique on three different puzzles and its lighthouse lights on your chart: mastered.
• The result card ticks the techniques you found, ready to share.
• Honest by design: no spot on a cell that cost a mistake, or with a hint open.

Learn sudoku on the Tide Chart

The Techniques screen charts 31 sudoku techniques, from Naked Single to X-Wing and XY-Chain, with the Rule of 45 among the Killer ones. Each has a one-minute lesson; most add practice puzzles made to need it and nothing harder. A calm way to learn sudoku, one technique at a time.

Sudoku hints that teach

Nudge shows where to look and never costs a coin. Explain names the technique and lights the cells that prove it: no cost on Easy, Medium or in lessons, three a day from Hard up, then coins. Fill it in writes the digit.

Fair sudoku, Easy to Extreme

• Six tiers, each set by the hardest technique a puzzle needs. Every sudoku has one solution and solves by logic, with no trial and error even at Extreme.
• Classic, Killer, Jigsaw and Diagonal boards.
• Killer Sudoku with few or no given digits, a cage helper that lists the digit sets for each sum, and the Rule of 45 taught like any other technique.

Daily sudoku with a weekly rhythm

• The Daily Puzzle is the same sudoku for everyone: Easy on Monday, rising to Master on Saturday, with a Jigsaw or Diagonal board on Thursday and Killer on Sunday. Past days wait in the calendar, and a full month wins a trophy.
• The Weekly Challenge: one hard board a week, Classic Master or Killer Expert in turn. Solve it in Classic or Strict with no hints and your time goes on the Play Games leaderboard.

A sudoku Journey of 600 levels

30 chapters bring in the techniques one by one and mix all four boards as the tiers rise, with stars on every level.

Mistakes your way

Classic allows three mistakes, Relaxed has no limit and hides wrong digits until you tap Check, and Strict stops at the first. Undo a quick mis-tap within three seconds and it is forgiven, once per puzzle.

Everything a sudoku player needs

Pencil notes and Fill notes, Undo and Redo, Erase, Restart, and a Pause that hides the board. Play cell-first or number-first; the row, column, box and matching digits light up, and conflicts are marked. Colour marks tint cells in four shades, and you can switch to a left-hand layout or a two-row number pad.

Calm and easy to read

• Four looks of our own: Paper Tide, Night Tide (a true dark mode), Sea Glass and high-contrast Harbour.
• Big digits, a text size setting, a timer you can hide and screen-reader labels.
• Musical digits: each digit plays its own note, and a finished row, column or box plays its own tune.

Coins and Play Games

Coins come from solving: first and clean solves, the Daily, the Weekly, Stretch puzzles and every technique you master. Spend them on Explain hints or one more chance in Classic. Google Play Games adds achievements and cloud save.

Sudoku offline

Every puzzle plays offline: the Journey, the Daily Puzzle and the Weekly Challenge come inside the game. 13 languages. Coin packs are optional.

A calm brain game, number puzzle and logic puzzle in one: learn sudoku as you play and solve Killer Sudoku offline.