The classic 9×9, done properly.
Every puzzle is generated fresh and guaranteed to have exactly one solution. Pencil marks, unlimited undo, a hint allowance and a clock that stops when you pause — and it all works with the plane in airplane mode.
Tap a cell and its row, column and box light up — every other 5 on the board lights up with it.
The tools a real Sudoku player expects, and nothing that gets in the way.
Jot candidates into a cell exactly like you would on paper, then commit when you have narrowed it to one.
Walk back as far as you like. Nothing is ever lost to a mistyped digit.
A hint allowance that scales with the grade — enough to unstick you, not enough to solve it for you.
A clock that stops the moment you pause, and a personal record kept separately for each difficulty.
A wrong digit costs you one of three. Enough room to think out loud, enough pressure to check first.
Progress is written after every single move, so closing the app mid-puzzle costs you nothing.
Difficulty is not guessed from the clue count. Every generated puzzle is solved by the same technique ladder a human would use, and graded by the hardest technique it actually needs.
| Grade | Clues | Reasoning it demands |
|---|---|---|
| Easy | 40–47 | Naked and hidden singles |
| Medium | 32–38 | + locked candidates |
| Hard | 27–32 | + naked and hidden pairs, triples, X-wing |
| Expert | 22–27 | Beyond the technique ladder — expect to guess and backtrack |
The Daily Challenge is seeded from the calendar date, so the grid you get is the grid everyone else gets.
Six packaged colour themes — three dark, three light — or your own photo behind the board, with a dim slider so the grid stays readable.
Twenty languages, each listed in its own script. Arabic flips the whole interface right-to-left.
Puzzles are generated on your phone, not fetched from a server. There is nothing to sign up for, nothing to log in to, and no loading screen between you and the next grid.
Coming soon to Android and iOS. Classic 9×9, four grades, one puzzle a day.
Sudoku