Star Battle: Two Not Touch

Star Battle, also called Two Not Touch or Queens: place stars on the grid so that every row, every column and every shape holds the same number, and no two stars ever touch — not even at a corner.

Every board here has exactly one answer, and every board can be reached by reasoning. That is not a promise in a description: a solver that shares no code with the generator counts the solutions and refuses anything with more than one, and a second solver that does no searching at all has to finish the board from empty before it is allowed into the app. A puzzle you could only crack by trying a placement and undoing it never ships.

75 boards in five sets, from a gentle six-by-six to nine-by-nine with two stars a line. These stay free, always.

A one-time unlock adds a second collection of exactly 300 more boards in three tiers — 27 easy, 160 medium, 113 hard — with the same single-answer, reasoning-only guarantee. The unlock can be restored at any time.

Tap a square once to mark it empty, twice to place a star. That is the whole of it.

What this app does and does not do:
- No advertising.
- Contains in-app purchases.
- No account and no sign-up.
- Gameplay works offline. The app communicates directly with the store you downloaded it from for product and price lookup, ownership and pending purchase recovery, buying or restoring the one-time unlock, and transaction acknowledgment. Store communication can happen at launch and on resume without a Buy or Restore tap; it never goes through a server of ours.
- Collects nothing about you.
- Completed-board markers and saved puzzle moves are kept on your device, and Android's own backup may include it if you have that switched on.
- Android permissions requested: android.permission.INTERNET. INTERNET is required by the app framework to load the app's own files from the device; the app makes no requests of its own.