Credits

• Chess pieces: the “cburnett” set by Colin M.L. Burnett, via Wikimedia Commons, used under the BSD 3-Clause license (one of the licenses it is offered under).
• Daily puzzles: selected from the Lichess puzzle database, released into the public domain (CC0). Each puzzle links to the game it came from.
• Openings: the Lichess chess-openings dataset, CC0.
• Opening statistics and example games: computed from the Lichess open database of rated games (CC0); engine evaluations from the Lichess evaluations database (CC0).
• Games database: over-the-board games from The Week in Chess (issues from 2012 onwards), © Mark Crowther, used with permission. Each game links to the TWIC issue it came from. Please support TWIC.
• Engine: Stockfish 19 via Stockfish.js (lite WebAssembly build), GPLv3 — runs unmodified in your browser on the analysis board; see source and licence.
• Move generation: chess.js (BSD 2-Clause).
• Fonts: Fraunces and Inter, SIL Open Font License 1.1.
• AI notes on game pages are written by Claude (Anthropic) from the stored Stockfish analysis.
• Built with Astro and hosted on Cloudflare Workers.

The full licence texts of chess.js, the pieces and the fonts are on the licences page. What the site stores about visitors, organisers and players is explained in the privacy notice.