LEGAL
Open-Source Attributions
The shoulders we stand on.
Bright Moves is grateful to the open-source community. This product includes software under permissive and copyleft licenses, including:
Per the GPL, corresponding source for GPL-licensed components is available on request. Full license texts ship with the application.
Regent chess piece set (AI-assisted)
Regent is an AI-generated visual design created in collaboration with Brightmoves. The Brightmoves owner authorized distribution and default use. No exclusive ownership or licence clearance is asserted.
Exact SVG hashes and provenance are available in the piece asset registry.
Stockfish
Position evaluation in the analysis workbench is powered by Stockfish, a free and strong UCI chess engine derived from Glaurung 2.1. We self-host Stockfish on our own infrastructure for full control over the eval pipeline and zero dependency on third-party uptime.
- Version: Stockfish 17.1
- License: GNU General Public License v3.0
- Source code: github.com/official-stockfish/Stockfish
- Authors: the Stockfish developers (see the project's AUTHORS file)
Stockfish is distributed under the GPL-3.0, which permits modification and redistribution under the same license. Bright Moves uses an unmodified, official Stockfish binary release, run only as a separate process over the UCI text protocol — it is not linked into any Bright Moves code, so the GPL's copyleft does not extend to our own software. Serving evaluations over HTTP is not itself conveyance; however, we package the Stockfish binary inside a container image that we transfer between our systems, which is conveyance of object code under GPL-3.0 §6. Accordingly we provide the Corresponding Source and a written offer for it — see “GPL-3.0 source & written offer” below.
Lc0 (Leela Chess Zero)
The human-like AI opponent is played by Lc0 (Leela Chess Zero), a neural-network chess engine, run as a separate process over UCI on our own infrastructure (it executes the Maia networks below). It is not linked into any Bright Moves code.
- Version: v0.31.2 (git 8ba8aa426460bbeda452754ff7d6a9bb60bb0e54), built from source on our infrastructure
- License: GNU General Public License v3.0
- Source code: github.com/LeelaChessZero/lc0
- Authors: The LCZero Authors
We use Lc0 unmodified. Because we convey it inside a container image, we provide its Corresponding Source and a written offer — see “GPL-3.0 source & written offer” below.
Maia Chess (maia-chess)
The opponent's human-like move choices come from the Maia Chess neural networks — models trained to play like humans at specific rating levels, by the Computational Social Science Lab (CSSLab) at the University of Toronto, together with Microsoft Research. The weight files themselves are the GPL-3.0 source form (no build reproduces a trained network).
- Release: v1.0 — rating bands 1100, 1300, 1500, 1700, 1900
- License: GNU General Public License v3.0
- Source / weights: github.com/CSSLab/maia-chess
- Authors: the maia-chess authors — CSSLab, University of Toronto, and Microsoft Research
We use the Maia weight files unmodified. Because we convey them inside a container image, we provide the Corresponding Source and a written offer — see below.
GPL-3.0 source & written offer
Stockfish, Lc0, and the Maia networks above are licensed under the GNU General Public License, version 3. Bright Moves packages these programs inside container images that we transfer between our systems, which is conveyance of object code under GPL-3.0 §6. To comply, we make the following written offer:
For at least three (3) years from the date we last conveyed the container image, we will give any third party who possesses the object code a complete machine-readable copy of the Corresponding Source for the GPL-3.0 components (Lc0, the Maia weight files, and Stockfish), for no more than our reasonable cost of physically performing the conveyance, or equivalent no-charge access to download it. The source corresponds to the exact pinned versions we ship (Lc0 v0.31.2; Maia v1.0 bands 1100/1300/1500/1700/1900; Stockfish 17.1). To request it, email legal at algebrics.com with the subject “GPL-3.0 Corresponding Source request — Brightmoves engine images”.
The same offer, the full GPL-3.0 license text, a copyright NOTICE, a pinned-hash source manifest, and a fetch/verify script are also shipped inside each engine image at /usr/share/doc/brightmoves-gpl/. We use all three programs unmodified (separate-process / UCI invocation only); no GPL-3.0 §5 modified-source obligation arises.
Fantasy & Spatial chess piece sets (Maurizio Monge)
Fantasy and Spatial are by Maurizio Monge under the MIT License. Brightmoves mechanically normalized the pinned Lichess SVG inputs with SVGO 3.3.2; CSS rules were inlined, styles converted to presentation attributes, and optimizer-safe metadata and IDs removed. No intentional visual-design change was made.
- Author: Maurizio Monge
- License: MIT
- Source pin: lichess-org/lila@f5b261e3d8ece6f511484e398cb8d81e37735bea
- Provenance:
public/pieces/registry.json
Full MIT License (available offline)
MIT License Copyright (c) Maurizio Monge Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chessnut chess piece set (Alexis Luengas)
Copyright 2015 Alexis Luengas. Licensed under Apache-2.0. Brightmoves mechanically modified the pinned SVGs with SVGO 3.3.2 by removing editor metadata and optimizer-safe IDs, converting styles to presentation attributes, and minifying syntax. No intentional visual-design change was made. Every modified SVG carries its own prominent change notice, original copyright and licence pointer. The pinned upstream commit contains no NOTICE file, so none has been invented.
- Author and copyright: Copyright 2015 Alexis Luengas
- License: Apache License 2.0
- Source pin: LexLuengas/chessnut-pieces@2b8eaf14a31edad7e9deb53b1473e1d4857868a9
- Provenance:
public/pieces/registry.json
Full Apache License 2.0 (available offline)
Apache License
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chess.js
Move generation, validation, and PGN parsing in the browser are handled by chess.js, licensed under the BSD 2-Clause License.
react-chessboard
The interactive board UI is react-chessboard, licensed under the MIT License.
Chess puzzles (Lichess open puzzle database)
Bright Moves puzzles are seeded from the Lichess open puzzle database, generated from games played on Lichess. This data is dedicated to the public domain under the Creative Commons CC0 1.0 Universal Public Domain Dedication. Lichess does not require attribution; we credit them gratefully. Lichess is free/libre open-source software. Bright Moves is not affiliated with or endorsed by Lichess.
Master games database (Lichess)
The Bright Moves “Master DB” games explorer is seeded from public games on Lichess, which publishes its game database under the Creative Commons CC0 1.0 Universal Public Domain Dedication. Lichess does not require attribution; we credit them gratefully. We index only cleared public figures (titled players) as searchable names; other players' games appear but are not a search key, and we honour removal requests at brightmoves648 at gmail.com. Bright Moves is not affiliated with or endorsed by Lichess.
Name-moderation wordlists
Bright Moves checks chosen usernames and display names against a multilingual list of slurs and obscenities, so that a name shown to a child is not abusive. Those lists are our own compilation — each term was selected, scoped and checked against real personal and place names by us. In assembling them we consulted publicly available compilations of offensive terms, chiefly the List of Dirty, Naughty, Obscene and Otherwise Bad Words, and we credit it here.
- Source consulted: LDNOOBW, © Shutterstock, Inc.
- License: CC BY 4.0
Other open-source dependencies
Bright Moves is built with Next.js, React, TypeScript, and dozens of additional open-source libraries. The full list of direct dependencies and their licenses is available in our public package.json. Each is used under the terms of its respective license.
Bright Moves is committed to honouring the licenses of the open-source software it depends on. If you believe we've missed an attribution or are out of compliance with a license, please contact us at legal at algebrics.com.
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