Classic Sudoku, endlessly generated.
Every puzzle is generated on your device and graded by the techniques it actually needs — not by counting how many digits it starts with. No ads, no timer nagging you, and a hint button that names the next move instead of making it for you.
An Android app. iOS is in development, with no date yet — get an email when it lands.
Sudoku is a 9×9 grid split into nine 3×3 boxes. Every row, every column and every box holds the digits 1 to 9 exactly once. You are given some digits and you work out the rest.
Nothing here is ever a guess. Every puzzle is solved by a logic engine at the moment it is generated, so a solution always exists and can always be reached by reasoning alone. If you are stuck, there is a move you have not spotted — not a coin to flip.
Graded by technique, not by clue count.
Counting givens is the usual shortcut and it is a poor one — a 30-given puzzle can be easier than a 34-given one. Grading by the techniques a solve actually requires means the label describes the thinking, not the visual density.
| Tier | What it is | What that changes |
|---|---|---|
| Easy | Singles only, 44+ givens | Naked and hidden singles are enough, and the next placement is usually close by. |
| Medium | Singles only, 36+ givens | The same techniques as Easy. Longer scans, and more of them — but never a new idea to learn. |
| Hard | Locked candidates and triples, 26+ givens | The first real jump. Singles alone stop being enough; a pointing pair or a naked triple is needed somewhere in every solve. |
| Expert | X-Wing, Swordfish, XY-Wing — no density floor | Shape-based techniques spanning several rows and columns, on grids left as sparse as the logic allows. Still solvable without guessing — that is a property of how they are generated, not an aspiration. |
Two hundred puzzles to start — fifty in each of the four difficulties.
Packs raise how many puzzles you can generate. Every price below is a one-off payment.
| Easy Pack | Adds 100 Easy puzzles | $1.99 |
|---|---|---|
| Medium Pack | Adds 100 Medium puzzles | $1.99 |
| Hard Pack | Adds 100 Hard puzzles | $2.49 |
| Expert Pack | Adds 100 Expert puzzles | $2.99 |
| Unlimited | Lifts the cap on all four difficulties, permanently | One payment |
Sudoku is the one game in the range that generates puzzles on demand rather than shipping curated packs, so a pack here raises your allowance rather than handing you a fixed set.
Difficulty packs are re-purchasable — buy more Easy puzzles as often as you like, without ever paying for Expert ones you will not play.
No subscription. Nothing expires.
Purchases are tied to the account you sign in with, so they survive a reinstall or a new device. Prices are US dollars; your local store will show its own.
Not fewer ads, not optional ads, not a "rewarded" video in exchange for a hint. There is no advertising code in the app at all, so there is nothing to interrupt you, nothing to accidentally tap, and nothing that starts appearing later once you are invested.
The Android advertising ID is absent from every one of our binaries, and none of them asks permission to read it. The Google library that can read it is not in the build at all. That is checked automatically on every release build before it ships — it is a property of the artifact, not a promise in a policy.
No name, no email address, no phone number, no contacts, no location. When you sign in, the platform offers the app your display name and avatar; the app never reads them.
Your identity with us is a one-way salted hash, computed separately for every game. The same person playing two of our games is two unrelated IDs, and we could not connect them if we wanted to — we removed the ability rather than promising not to use it.
No subscriptions. No expiring content. No energy timer, no "come back tomorrow", no currency to top up. You buy a puzzle pack and it is yours, on every device you sign in from.
Anonymous gameplay measurements: how long a puzzle took, whether it was finished, how many hints it needed. We use them to check that a puzzle labelled Hard is actually hard. Saying that plainly is stronger than implying nothing is measured — the privacy policy spells out every field.
You should not have to take our word for any of it. See the receipts