Most chess players analyze one game at a time and move on. Blackbox looks across all your games to find what you keep doing wrong — and ranks it by how much it’s actually costing you.
Import a PGN file or connect your Lichess or Chess.com account. No account required. The more games you provide, the clearer your patterns become.
Every move across every game is evaluated by Stockfish. No guesses, no coaching heuristics — just engine-level accuracy applied to your whole history, not just one game.
Your recurring mistake types are identified and ranked by how damaging they are — not just how often they appear. You see your #1 leak, why it keeps happening, and where it showed up in your actual games.
Blackbox isn’t a coach and it doesn’t teach opening lines. It does one thing: finds the specific mistake patterns that are costing you rating points across your real games, ranked by severity. Everything it tells you comes directly from Stockfish — nothing invented.