Sudoku built for the fold.
Calm, classic Sudoku where the board never sits on the crease, and your game follows you from the cover screen to the big screen.
Fold it, open it, stand it up.
Crease rearranges itself for however you're holding your phone. Unfold mid-game and nothing is lost: your selection, notes and timer come with you.
Graded by technique, not clue count.
Every puzzle has exactly one solution. A built-in solver grades each one by the hardest technique it needs, so "Hard" always means hard.
- EasyNaked and hidden singles
- MediumPointing, box/line reduction, pairs
- HardTriples and X-Wing
- ExpertSwordfish and XY-Wing
- MasterChains and forcing logic
Learn the move, not just the answer.
A hint first points out any mistake. Otherwise it names the technique that unlocks the next cell and explains why, so you get a little better every game.
“3 cells in row 7 can only hold 5/8/9, so those digits can't go anywhere else in that row. Then: 9 has only one place left in column 1.”Naked triple → Hidden single · Fill in 9
Thoughtful details.
Everything you'd expect from a great Sudoku app, and nothing you wouldn't.
A daily puzzle
The same challenge for everyone: gentle on Mondays, fiendish by the weekend. Keep your streak alive.
Pencil notes
Long-press any number to pencil it in. Notes clean themselves up when you place a digit.
Unlimited undo
Every move, including the notes it tidied up, can be taken back.
Dark mode
A paper-calm board by day and a soft, dark one at night.
Stats and best times
Track solves and personal bests for every level.
Private by design
Works fully offline. No ads, no accounts, no tracking. Privacy policy