Support

Yes. No subscription, no in-app purchases, no ads. It's open source under the AGPL-3.0.

Each repertoire is a PGN file in iCloud Drive, in the ORBT Chess folder (Files app on iPhone and iPad, Finder on the Mac). Without iCloud they're in the app's Documents folder. Every edit is saved immediately. Settings and training progress are in files next to it (.otrep.json and .otlog.jsonl), never inside the PGN.

In the repertoire list, choose Import and pick the file. It's copied into the ORBT Chess folder; the original isn't changed. A PGN with several games from the starting position becomes one repertoire.

It's how often you'd reach that position in your games, from the opening explorer's statistics. Each repertoire has a coverage target, such as “cover moves seen once in 500 games”: opponent moves more common than that count as gaps until you add a reply.

You choose per repertoire: Lichess Blitz or Rapid games at a rating range, or Classical over-the-board games since 2000 by FIDE rating (Lumbra's Gigabase). Offline coverage tables for your choice are downloaded once, so most checks need no network.

No. The offline coverage tables answer most positions without one. Lichess's opening explorer only answers signed-in users, so sign in (Settings) for live statistics on positions the tables don't hold. If statistics stop loading for a minute, Lichess is limiting the rate of requests; the app waits and continues on its own.

Every position where it's your move is a card, scheduled with Anki's algorithm (FSRS). You play through whole lines from the start, and one line answers every due move on it. You can also drill everything under a single branch, and it all works offline.

Yes. Stockfish runs on your device with a small built-in network. For stronger analysis, download the full network in Settings. Lichess cloud evaluations are used first when you're online.

When iCloud reports a conflict, ORBT merges both versions of the repertoire, its settings and its review history, so no line or review is lost.