Yomoe: Sudoku

Boards from 4×4 to 16×16, each generated on your device with one solution.

A quiet study, one puzzle at a time. Made in Japan.

Yomoe Sudoku is made by Yomoe Studio, a small studio in Japan that does nothing but build apps. No flashy effects, no nudges to spend. Our time goes into the details instead — the feel under your finger, the colours, the quality of each individual puzzle — to make something you can pick up every day without being worn out by it.

Yomoe Sudoku brings the feel of pencil on paper to your phone. Every puzzle is generated on your own device and checked to have exactly one solution. No connection needed — on a plane, underground, or anywhere else, your next puzzle is already there.

■ When 9×9 is no longer enough — boards up to 16×16 Challenge mode gives you five board sizes — 4×4, 6×6, 8×8, 12×12 and 16×16 — each with four difficulties. Numbers above 9 are shown as letters A to G, so no cell ever has to squeeze in two digits. Boards of 12×12 and larger can be pinch-zoomed, and a long puzzle can be saved and picked up later. Every Challenge puzzle is verified to be solvable by logic alone, with no guessing, before it is handed to you. Finishing a 16×16 feels nothing like finishing a 9×9.

■ Six ways to play

• Classic: pick Easy through Expert and solve one at your own pace.
• Challenge: five board sizes from 4×4 to 16×16, each with four difficulties.
• Daily Challenge: one puzzle a day, the same one for everyone in the world. Stamps fill your calendar and your streak grows.
• Journey: level after level, chapter by chapter — from gentle 4×4 grids up to Expert.
• Speed: a timed single puzzle, plus a sprint that keeps them coming.
• Zen: no timer, no mistake count. A calm, low-contrast board and nothing but thinking.

■ Help that teaches Candidate notes, row/column/box highlighting, and matching-number emphasis. When you are stuck, a hint tells you why that digit belongs there — so you learn the technique, not just the answer. Slips can be undone as many times as you like.

■ Worth coming back to Best times and three-star rates per mode and difficulty, separate records for every board size, achievements and trophies, and your daily streak. There are no leaderboards to compete on. The only one you are measured against is yesterday's you.

■ Built to be comfortable Everything within reach of one hand, a left-handed mode, and colour-blind friendly marking. 10 languages. Portrait only.

■ Pro version (one-time purchase)

• No ads
• Unlimited hints (free: 3 per puzzle, plus more by watching a video)
• All 5 board themes unlocked (Study Paper, Night Ink, Celadon, Ochre, Bamboo Dew) The free version still gives you all six modes, every board size including 16×16, every level, and every achievement and statistic, with nothing held back. Pro only buys you an uninterrupted screen and a change of scenery.

■ Tell us what you think Anything you notice, anything you would like to see — send it through the feedback form in the app. We read every message that comes in, and it shapes what we build next.