Open Source Notices

Last updated: September 3, 2026

Grandmaster Journey includes open-source software. This page lists components that require attribution or license notices under their terms.

Stockfish chess engine

This app uses the open-source Stockfish chess engine (bundled as stockfish-lite-js, Stockfish.js 18) to power evaluations, computer opponents in daily challenges, and related analysis features. Stockfish is copyright its respective authors and licensed under the GNU General Public License v3 (GPLv3).

The engine runs in an isolated WebView and communicates with the app only through standard UCI text commands. The app's proprietary UI and server code are separate from the engine binary.

Chess piece artwork

Optional chess piece artwork is adapted from themes published in the Lichess open-source project. Each set is © its respective author; license terms are listed in Lichess's copying file. Grandmaster Journey is not affiliated with Lichess.

Firi

The optional Firi piece theme is artwork by James Faure, used under the Creative Commons Attribution 4.0 International (CC BY 4.0) license.

Şahî Ivory Brown

The optional Şahî Ivory Brown piece theme is artwork by Tamer Karatekin (DeepSeaChess LLC), used under the Şahî Chess & Shatranj Font License v1.0. The graphics in this app are unmodified exports, as required by that license.

Pixel

The optional Pixel piece theme is artwork by therealqtpi, distributed via Lichess under the GNU Affero General Public License v3 or later (AGPLv3+). PNG assets in this app are derived from the upstream SVG sources.

• Stockfish.js source (engine build used in this app)https://github.com/nmrugg/stockfish.js
• Upstream Stockfish projecthttps://github.com/official-stockfish/Stockfish
• GNU General Public License v3.0https://www.gnu.org/licenses/gpl-3.0.html
• Lichess piece set licenses (COPYING.md)https://github.com/lichess-org/lila/blob/master/COPYING.md
• Firi piece set: James Faure (source repository)https://github.com/jfaure/Firi-pieceset
• Creative Commons Attribution 4.0 Internationalhttps://creativecommons.org/licenses/by/4.0/
• Şahî Chess & Shatranj Font License (full text)https://github.com/TamerKaratekin/shahi-chess-shatranj-font/blob/main/LICENSE.txt
• Tamer Karatekin / DeepSeaChess: Şahî Chesshttps://www.deepseachess.com/shahi
• Pixel piece set: upstream SVG source (Lichess)https://github.com/lichess-org/lila/tree/master/public/piece/pixel
• GNU Affero General Public License v3.0https://www.gnu.org/licenses/agpl-3.0.html

Grandmaster Journey is an independent application and is not endorsed by or affiliated with the official Stockfish development team or Chess.com.

If we add other open-source components that require notices, we will list them here.