About GChess Review

GChess Review is a free chess site that runs in your browser. Look up any player's games on Lichess or Chess.com, open one, and every move gets a verdict, from Brilliant to Blunder, with the engine's better line beside each mistake. There is also a puzzle library and a club of bots to play against.

How a review works

The analysis is done by Stockfish 19, the strongest open-source chess engine, compiled to WebAssembly and run on your own computer. Nothing is sent to a server of ours, because there is none.

1. Find the game. Type a Lichess or Chess.com username, or paste a PGN from anywhere. Your browser asks that site for the player's public games.
2. A quick pass. The engine looks at every position once, to find the moments where the evaluation swung.
3. A closer look. It spends more time on those moments, then classifies each move by how much it cost against the best move available.
4. Step through it. The review opens where the game turned. You can play your own moves from any position to see what would have happened.

What else is here

• Puzzles. Nearly 10,000 positions from the Lichess puzzle database, in five themed books from openings to endgames, plus mixed sessions. Your progress stays on your device.
• Bots. Six club regulars who talk while you play, from a nervous beginner to an engine that never blunders, with an optional coach.

Learn more

The guides explain what each move label means and how a review is made.

Your data

There are no accounts. Searches, puzzle progress and settings are kept in your browser's storage on this device, and clearing the site's data removes all of it. The privacy page lists everything kept and everything sent.

Who makes it

GChess Review is an independent project. It is not affiliated with Lichess, Chess.com or the Stockfish team. Questions, bugs and ideas are welcome on the contact page.