About and credits

ChesStresS is an independent chess game. It is not affiliated with, endorsed by or connected to FIDE, Lichess, Chess.com, the World Series of Poker, PokerStars or any other organisation. Contact: [email protected].

In-game ranks

Ranks such as Newcomer, Grandmaster I–XII and Super GM XIII are levels inside this game, earned by playing here. They are not FIDE titles and say nothing about a player's official title or rating. Ratings shown in the game are ChesStresS ratings – CSR (ChesStresS Rating) for chess games and TSR (Turbo StresS Rating) for Turbo Live – not FIDE ratings. How they are calculated: How ratings work.

Chess engine

Computer opponents, game review and analysis use Stockfish (the Stockfish developers, see the AUTHORS file of the Stockfish project), compiled to WebAssembly. Stockfish is free software licensed under the GNU General Public License version 3 (GPLv3). Its licence text is included with the game (Copying.txt). Source code of Stockfish: github.com/official-stockfish/Stockfish.

The client part of ChesStresS that runs on your device and works with Stockfish is distributed under the GPLv3. Its complete source code is available free of charge to everyone: Source code. The ChesStresS server is a separate service and is not distributed.

Pieces, fonts and data

Chess pieces: the classic "cburnett" piece set by Colin M.L. Burnett, used under its free licence (GPLv2 or later / CC BY-SA 3.0); source: Wikimedia Commons.
Fonts: UnifrakturMaguntia (© 2010 j. 'mach' wust), Playfair Display (© 2017 The Playfair Display Project Authors) and Libre Baskerville (© 2012 The Libre Baskerville Project Authors), licensed under the SIL Open Font License 1.1. They are included with the game, unchanged except for WOFF2 compression; licence text: fonts/OFL.txt. No font service is contacted.
Move rules: chess.js by Jeff Hlywa and contributors, BSD 2-Clause licence.
Puzzles: puzzles from the Lichess open puzzle database (database.lichess.org), released into the public domain (CC0), with thanks to Lichess; plus original puzzles generated by ChesStresS from engine games.
Sounds: generated in the app; no recorded sound samples are used.
App shell: Capacitor (Ionic), MIT licence.

Music

Intro music: the opening of “Rain-Signed Contract” by Three Border Collies, from the album The Handling Officer, used by the operator, who owns it. Turn it off in Settings › Intro music or with the speaker button on the intro.

Fairness

Computer opponents are always labelled as such. Online games are against people; where the computer takes a side or a seat (a team with nobody online in Turbo Live, an empty seat at a four-player table), this is shown. Reports of unfair play are reviewed by a person; there are no automatic bans. See Safety & reporting.