Open-source licenses

1. Application software — GNU GPL v3

Xiangqi Trainer source code, native modules (including those linked with Pikafish), and our modifications are licensed under the GNU General Public License version 3 or later. You may use, modify, and redistribute that software under the GPL.

There is no warranty. The software is provided in the hope that it will be useful, but without even the implied warranty of merchantability or fitness for a particular purpose.

• GNU GPL version 3

2. Pikafish

Pikafish is a UCI xiangqi engine derived from Stockfish, copyright the Pikafish authors, licensed under GPL-3.0-or-later. The App compiles and runs Pikafish on device (mobile) or as a sidecar binary (desktop).

Pikafish neural-network training data is made available under the Open Database License (ODbL).

• Pikafish on GitHub
• Open Database License (ODbL)

3. Corresponding Source

Under GPL v3, we offer Corresponding Source for the GPL-covered software in our distributed builds (App Store, Google Play, and desktop) — including Pikafish, our bridge and modifications, and the application source needed to rebuild that binary.

This offer is free of charge, valid for at least three years and for as long as we support the product. Email xiangqitrainer@gmail.com with the app version (for example 1.1.7) and platform. We will provide the source over the network at no charge.

• xiangqitrainer@gmail.com

4. Not covered by the GPL

The following are not licensed under the GPL. They remain under their respective copyrights and are provided for use inside the App only:

• Classical xiangqi book texts and translations
• Catalog indexes and encrypted item payloads
• Trademarks, product name, and original artwork / branding