Chessomnia

Chessomnia turns your tablet or phone into a chess board. Two players, one device, sitting opposite each other — exactly as you would at a real board. And when nobody else is around, the board plays: four strengths, from one a nine-year-old can beat to a good club amateur. FREE. NO ADS. NO ACCOUNT. NO TRACKING. Those four are the point, and none of them has an asterisk. Free means free — not a trial, not a lite version, nothing to unlock, no in-app purchases. No advertising and no analytics. No account, no sign-up, no email address: you install it and you play. And the tracking claim is not a promise, it is a property. The app holds no Android permission that grants it anything — not even internet access — so it is technically incapable of sending anything anywhere. Your games never leave your device. You can verify that yourself: Chessomnia is open source. WORKS COMPLETELY OFFLINE Nothing to connect to. On a plane, in a cellar, in a tent — no difference. The app has no server side at all, and the opponent runs on your device rather than somewhere else. A REPLACEMENT FOR THE BOARD The point is the two people at the table. Chessomnia takes over exactly the jobs a wooden board cannot do: • It knows every rule, including castling, en passant, promotion, the fifty-move rule, threefold repetition and dead positions. • It never lets an illegal move through, and it never misses a checkmate. • It keeps the pieces where you put them when the device goes to sleep. AN OPPONENT WHEN NOBODY ELSE IS AROUND Play the device instead of a person, in the colour of your choice. Four strengths: the weakest is meant for a child of nine to eleven — it keeps its own position together but walks past most of what you leave hanging — and the strongest is a good club amateur, deliberately not as strong as it could be. An opponent nobody can beat is not a feature. Take a move back against it and it is your turn again, not its. A LEARNING AID, NOT A TEACHER Tap a piece and every square it may legally move to is marked — with castling and en passant highlighted separately, because those are the moves beginners overlook. Switch the hints off once you no longer need them. What you will never get is a suggestion of which move to play, or a bar telling you who is winning. The opponent makes its move and says nothing about your position. Working that out is the game. BUILT FOR A DEVICE LYING FLAT ON THE TABLE A tablet suits it best. A phone works just as well: the board is smaller, nothing else changes. Everything follows from that one idea: • Clock, status and buttons exist twice, once at each player's edge, so neither of you is reading upside down. • The pieces of the player opposite are drawn rotated — the job a real piece's shape does at a wooden board. • "Turn the board" rotates it in place, instead of somebody having to pick the device up. • Prompts and the promotion dialog turn to face whoever triggered them. • When a game ends, nothing covers the board. After a mate you want to see why — the highlighted king and the marked last move are the answer. A CLOCK THAT INFORMS RATHER THAN JUDGES The clock counts upward: it shows how long each player has thought in total. It never runs out, and it never ends a game. At a home board that is what a clock is for. Switch it off entirely if you prefer. Take a move back and the thinking time comes back with it — the way a takeback actually works among friends. CORRECTNESS YOU CAN CHECK The rules engine is verified against 12.4 million positions of standard perft tests and cross-checked against an independent implementation across 4,576 positions, deliberately dense around checkmates and stalemates. If it ever does get something wrong, the built-in "Report a problem" produces the exact text needed to reproduce it — including every move that was legal in the disputed position. OPEN SOURCE Apache-2.0. Read it, build it, fork it: https://github.com/alramlechner/Chessomnia