Credits

Hearth Chess was created by Christian Fobian.

Free and open-source work that Hearth Chess is built on

This site stands on other people's generosity. Here is what it uses, who made it, and under which license. Thank you to everyone listed.

The chess engine

• Stockfish by the Stockfish developers. It plays the opponent, grades every move, finds hints and builds the puzzles. License: GNU GPL v3. It runs as a separate program next to the website, and its source code is available from stockfishchess.org and from the Debian package.
• chess.js by Jeff Hlywa and contributors. It knows the rules of chess in the browser and on the server. License: BSD 2-Clause.

Chess pieces

The piece artwork comes from the Lichess open-source project. Each set keeps its author's license:

• Cburnett by Colin M.L. Burnett (GPL v2+)
• Merida by Armando Hernandez Marroquin (GPL v2+)
• Chessnut by Alexis Luengas (Apache 2.0)
• Mpchess by Maxime Chupin (GPL v3+)
• Celtic, Spatial and Fantasy by Maurizio Monge (MIT)
• Pixel by therealqtpi (AGPL v3+)
• RhosGFX by RhosGFX (CC0 1.0)
• Kosal by Kosal Sen (CC BY 4.0)
• Staunty, Cardinal, Tatiana, Maestro, Fresca and Gioco by sadsnake1 (CC BY-NC-SA 4.0, non-commercial use)

Opening names

The list of named openings, with their ECO codes and move lists, comes from the lichess-org/chess-openings project, released into the public domain (CC0).

The software underneath

• Node.js runs the server (MIT).
• Express handles web requests (MIT).
• mysql2 talks to the database (MIT).
• MariaDB stores accounts, games and progress (GPL v2).
• bcrypt.js scrambles passwords so they cannot be read (MIT).
• tini and Debian make up the container the site runs in (MIT and various open-source licenses).

Questions about a credit or a license? Contact .