Free chess game review that tells you why.
Paste a game or enter your username. Get accuracy, mistakes and key moments in seconds, with a reason you can check on the board for every one.
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Key moments:
- 1. 10.Nxb5, great move: Only this move works here. The runner-up, Bxf6, would leave you at about +0.9; your move keeps you clearly better (about +3.0).
- 2. 10...cxb5, inaccuracy: The engine prefers Qb4+, which limits the damage (about −3.1).
- 3. 12.O-O-O, great move: Only this move works here. The runner-up, Bxf6, would leave you at about +2.3; your move keeps you clearly better (about +5.1).
- 4. 14.Rd1, great move: Only this move works here. The runner-up, Bxf6, would leave you at about +2.6; your move keeps you clearly better (about +5.8).
- 5. 16.Qb8+, great move: Only this move works here. The runner-up, Qb7, would leave you at about +2.8; your move forces mate in 2.
- 6. 17.Rd8#, great move: Only this move works here. The runner-up, a3, would leave you at about −5.0; your move forces mate in 1.
98.2 Paul Morphy82.8 Duke Karl / Count IsouardOpen the example →
What a review gives you
Accuracy and honest labels
Every move checked by Stockfish, and every suspected mistake checked again, deeper, before we call it a blunder. Each label carries its symbol: ?! inaccuracy ? mistake ?? blunder.
Key moments, with reasons
The three to six moves that decided the game, each with what happened and what to play instead, shown on the board.
Your leaks across games
Enter a username to see the mistakes you repeat over your recent games, with your own positions as examples. See an example report.
How it stays honest
Checked twice
A quick pass finds the candidate mistakes. Each one is then searched again at a greater depth, and only the ones that hold up get a label. Those moments are marked “checked deeper”.
Every reason has its line
Each explanation comes with the moves that prove it. Tap the line and it plays on the board, so you never have to take a sentence on trust.
The engine runs on your device
Stockfish runs inside your browser as an unmodified open-source build. Your game isn't uploaded for the free review. Licences and source code.
Questions
Is the game review free?
Yes. The full engine review is free: accuracy, move labels, key moments and the reasons behind them. There are no ads and no daily limit. A paid Coach that writes plain-language notes at your level is planned as an extra, and the free review will not shrink when it arrives.
Do I need an account?
No. Paste a PGN or type your Lichess or Chess.com username and press Review. Nothing to sign up for, and we remember your last username in your browser so the next review is one click.
Is my game uploaded anywhere?
Not for the free review. The Stockfish engine runs inside your browser, so your moves stay on your device. If you import by username, your browser asks Lichess or Chess.com for your public games directly.
How is accuracy calculated?
Each position gets a winning chance from the engine evaluation. Every move is scored by how much winning chance it gave away, and your accuracy combines those move scores across the game. Suspected mistakes are checked again at a greater depth before we label them.