Upload games, run engine analysis, and get a report that shows exactly where you leak rating — objectively.
Upload a PGN file or import games from a Lichess account.
No account required. We only analyze your moves.
Each move is evaluated using Stockfish to detect opening deviations, evaluation drops, and recurring patterns.
No guesses. No coaching heuristics.
Get a clear report showing exactly where your games start to go wrong — including the first move where you leave theory and lose advantage.
Blackbox Chess is an engine-driven analysis tool.
It doesn’t teach lines or tell you what to think.
It shows you what the engine sees — objectively.