About

A free, open chess game analyser — built it because I can.

Why this exists

I play chess as a hobby, and I was annoyed that proper game review is stuck behind a paywall. I also tried several other free alternatives on the internet, but I personally felt they were very inaccurate many a times — and I don't mean this as disrespect to their creators, just my opinion. That made me think, why pay for game review when I can build my own tool to do that.

It was also uni break and I was bored, so I wanted a project that would actually eat up my day instead of wasting it. Game review seemed like a good problem to dig into — engine eval, move classification, working out why an exchange sac should count as brilliant instead of just getting flagged as a blunder that happened to work out.

What it does

Move-by-move classification

Every move in a game gets labelled — brilliant, great, best, good, inaccuracy, mistake, blunder — the same vocabulary you already know from Chess.com, computed locally with Stockfish.

Import from Chess.com or Lichess

Drop in a username and pull recent games straight from either site, or paste a PGN directly. No account needed on SacTheRook's end.

Game accuracy, the Lichess way

Accuracy percentages are computed with the same win-percentage-based formula Lichess uses, not a flat centipawn-loss average, so accuracy actually reflects how much a mistake cost at that position.

Contact

Questions, bug reports, or feedback — bolt9573@gmail.com or on Instagram @bolt.dev5