Free sudoku that explains itself
Ninefold is a calm, ad-free sudoku for your phone or computer. Every puzzle has exactly one solution and can be solved by logic alone, and every level is graded by the hardest technique a person needs, not by counting clues. Stuck? A hint points you at the right row, column or box, names the technique, and explains it in plain words before it ever fills a square.
How to play sudoku
Fill the grid so every row, every column and every 3×3 box holds the digits 1 to 9 once each. Tap a square, then a number. Turn on Notes to pencil in candidates, or let Ninefold fill them in and keep them tidy as you go. Hold a number to lock it and fill squares with single taps.
The five levels
- Easy: plenty of clues; full houses, naked and hidden singles.
- Medium: fewer clues, and pointing or claiming (locked candidates).
- Hard: naked and hidden pairs and triples.
- Expert: X-Wing, Skyscraper, 2-String Kite, Y-Wing, XYZ-Wing and Swordfish.
- Evil: W-Wing, Jellyfish, simple colouring, unique rectangles and XY-chains.
Killer Sudoku
Killer Sudoku has the usual rules plus cages: dashed shapes with a total in the corner. The digits in a cage add up to its total and never repeat. Learn the Rule of 45 (every row, column and box adds up to 45) and the combinations for each cage size, and the grid opens up.
Twofold
A sliding number game in the style of 2048: swipe to move every tile, and two equal tiles merge into their sum. Reach 2048, then keep going.
Questions
Is it free? Easy, Medium and Hard are free and unlimited, along with the Daily, Twofold, notes, highlighting, undo and stats. Ninefold Pro, a one-time $2.99 upgrade, adds Expert and Evil, Killer Sudoku, unlimited hints and premium themes.
Is my data private? Yes. There are no accounts and nothing leaves your device. It works offline after the first visit.
All Yuzool apps · Sudoku is a traditional logic puzzle; Ninefold is an independent implementation.