Blackbox Chess analyzes your last 10 to 100 chess games using Stockfish, identifies the mistake types that repeat across your game history, and ranks them by how much rating points they cost you. No account required to start.
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 Chess 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.
Lichess and Chess.com analyze one game at a time. They're good at showing you where you blundered on move 23. What they can't tell you is which mistake you repeat across your last 50 games, or which one is actually costing you the most rating points.
Blackbox Chess looks across your entire recent game history and groups errors by type. The output isn't "you hung your bishop on move 14," it's "hanging pieces is your #1 recurring mistake, it appeared in 7 of your last 10 games, and here's why it keeps happening." That's the gap this fills.
A one-off report finds your pattern. The $12/mo subscription keeps working on it. Each week we pull the games you have played since last time, analyze all of them, and show whether your mistake rate is actually trending down.
The positions you got wrong resurface on a spaced-repetition schedule until they stick, you can replay the exact endgames you misplayed against perfect tablebase play, and a free personalized opening video credit lands every week. Cancel any time; access lasts to the end of the period.
With a paid report, you can also get a short narrated video for each opening where you consistently leave book, built from your own games. Pick the openings you want, and we generate and email each one to you, usually within an hour. Starting at $5 per video, less as you add more.
You can also earn free videos: share a delivered video on Instagram, TikTok, YouTube, or Facebook, tag ChessJitsu, and submit the link. Each approved share earns one free video credit.