Open-source notices

Built-in chess engine

The computer opponent in Artha Chess is the Chess Challenge Engine, a separate program that is free software under the GNU General Public License version 3. Its licence text and source code are included in the engine folder of every Artha Chess installation, and are also available — together with build instructions and the source of the libraries it uses — at engine.arthachess.com.

The engine's search is adapted from Obsidian by gab8192 (GPL-3.0), its evaluation values are ported from Cheese by Patrice Duhamel (GPL-3.0), and it uses python-chess by Niklas Fiekas (GPL-3.0-or-later).

Piece set

Chessnut pieces — Copyright 2015 Alexis Luengas, Apache License 2.0, github.com/LexLuengas/chessnut-pieces. All other piece sets and the program icon are original work.

Program components

Artha Chess also includes Python, pygame, SDL and other components, each used under its own licence. The complete notices are installed with the program in the licenses folder and published here: third-party-notices.txt.