Software & artwork licenses

Chess board and pieces

The board uses react-chessboard and its drag-and-drop components under the MIT license. The chess piece artwork is by Colin M. L. Burnett, used under its BSD three-clause license option.

Read the copyright notices and licenses.

Outfit typeface

The trainer uses Outfit, by the Outfit Project Authors, under the SIL Open Font License 1.1.

Stockfish analysis engine

Browser exploration uses the unmodified Stockfish.js 18.0.8 lite single-threaded engine, distributed under the GNU General Public License, version 3. Stockfish.js is copyright Chess.com, LLC and builds on the work of the Stockfish contributors.

• GPL version 3 license
• Engine contributors
• Download the engine source and required neural network
• Build instructions and source provenance
• Version information and checksums
• Neural-network CC0 license

The engine is provided without warranty, as described in its license. You may copy, modify and redistribute it under that license.