About Play Chess

Play Chess is for one game with someone you know. Open the site, send the link or show the QR code, and play. Neither of you signs up.

Every move is checked against the rules on the server before the other board sees it, and the server runs the clocks. A modified browser cannot slip in an illegal move or stop its own clock.

The rules engine is chess.js by Jeff Hlywa, under the BSD 2-Clause licence. The same code checks moves in your browser and on the server.

On your own, you can play the computer: levels 1–5 here in the browser, higher levels in the Play Chess app. The computer runs inside your browser on models we trained ourselves. The hint, game review and analysis board on these pages use a small engine we wrote. Neither is Stockfish.

There is no rating, no matchmaking with strangers and no chat.