Backbox Chess runs Stockfish across your last 10–100 games and identifies the specific mistake types that keep costing you, ranked by how damaging they actually are. Not one game reviewed. Your chess, diagnosed.
What is Backbox Chess? Backbox Chess is a free web tool that 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 many rating points they cost you. Connect your Chess.com or Lichess account, or upload a PGN file — no sign-up required. The free analysis covers 10 games and names your #1 recurring mistake. The full report ($10) covers 100 games, ranks all patterns by severity, and includes a targeted fix course built around your specific weakness.
Import a PGN or connect your Lichess or Chess.com account. The more games, the clearer the pattern.
Every move, every game. Not a single game reviewed, your whole history scanned for what keeps going wrong.
See your recurring patterns ranked by how much they're actually costing you, so you know exactly what to fix.
Analyze up to 10 games free. No account. No credit card. Takes about 60 seconds.