Credits & licenses

This trainer is built on other people's generous work.

Opening lines

The openings come from lichess-org/chess-openings, a catalog of named opening lines maintained by the Lichess community and released into the public domain under CC0 1.0. The lines were grouped into one file per opening family and arranged as flash cards for this site.

Chess pieces

The pieces are the “cburnett” set by Colin M.L. Burnett, from Wikimedia Commons. The author offers them under GFDL, CC BY-SA 3.0, GPL or the 3-clause BSD license; this site uses them under the BSD license below. They were changed only to add a viewBox so they scale with the board.

BSD 3-Clause license for the pieces
Copyright (c) 2006, Colin M.L. Burnett
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors
   may be used to endorse or promote products derived from this software
   without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

Typefaces

Bricolage Grotesque, Atkinson Hyperlegible and JetBrains Mono, served by Google Fonts under the SIL Open Font License.

Software

Move rules by chess.js (BSD 2-Clause). PGN parsing by @mliebelt/pgn-parser (Apache 2.0). Built with React Router (MIT).