Licenses & credits

Endgame is built on generous open-source work. Thank you to everyone below.

Endgame itself

Stockfish

Chess engine by the Stockfish developers (T. Romstad, M. Costalba, J. Kiiski, G. Linscott and many contributors), compiled to WebAssembly as stockfish.js by Nathan Rugg. License: GPLv3 — full text. Source: official-stockfish/Stockfish and nmrugg/stockfish.js (v19.0.1, "lite single-threaded" build, unmodified).

chessground

Interactive board by the Lichess team, lichess-org/chessground. License: GPLv3 or later. Board colours on this site are our own.

chess.js

Chess pieces

"cburnett" piece set by Colin M.L. Burnett, distributed with chessground. License: GPLv2 or later (also available under CC BY-SA 3.0 / GFDL).

Puzzles

Tactics positions are a sample of a few thousand puzzles from the Lichess open puzzle database, released under Creative Commons CC0. Each puzzle links back to its Lichess source. Endgame is not affiliated with Lichess.

Opening notes

The opening repertoire, traps lab notes, Path lessons and all explanatory text were written for Endgame.

Classic games

Game scores (the moves themselves are historical facts) were checked against the PGN Mentor player files and validated move-by-move with chess.js; Lasker–Thomas 1912 was checked against its published score. All commentary on this site is original Endgame text.

Coach-inspired paths

Some Path lessons say “Inspired by …” and link to a creator's official channel (GothamChess, Goofy Tushar, Anna Cramling, Hikaru Nakamura). The lessons are original text about publicly known teaching themes; no videos, scripts or course material are reproduced. Endgame is not affiliated with or endorsed by any of these creators, nor by Lichess, Chess.com or the Stockfish project.

Sounds & art

Sound effects are synthesized in the browser (WebAudio). The Endgame logo, world banners and UI are original.