ChessNotes (https://chessnotes.app) - Stockfish chess engine notice
Last verified: 2026-10-01

WHAT WE DISTRIBUTE
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ChessNotes serves pre-built WebAssembly/JavaScript builds of the Stockfish
chess engine from https://chessnotes.app/stockfish/. Your browser downloads
one of them and runs the engine locally, in a Web Worker, as a separate
program: the ChessNotes app only exchanges text commands with it over the UCI
protocol (postMessage). ChessNotes's own code is not linked into the engine.

Stockfish is free software, licensed under the GNU General Public License,
version 3 (GPLv3). The full licence text is at:
  https://chessnotes.app/licenses/GPL-3.0.txt

  Stockfish - Copyright (C) 2004-2026 The Stockfish developers
  (Tord Romstad, Marco Costalba, Joona Kiiski, Gary Linscott and the
  contributors listed in https://chessnotes.app/licenses/stockfish/AUTHORS.txt)

  Stockfish.js (WebAssembly port) - Copyright (c) 2026 Chess.com, LLC
  by Nathan Rugg, https://github.com/nmrugg/stockfish.js - License: GPLv3

This program comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law (GPLv3 sections 15-16). You may redistribute it under the
terms of the GPLv3.

UNMODIFIED. Every file listed below is byte-for-byte identical to the file
of the same name in the "stockfish" npm package, version 19.0.0, published
from the commit named below (SHA-256 compared on 2026-10-01). ChessNotes has
made no changes to the engine.

1) ENGINE BUILDS USED BY THE APP: Stockfish 19 (Stockfish.js 19.0.0)
--------------------------------------------------------------------
The app picks one build per device: the full build on computers, the lite
build on phones and tablets (and as a fallback when the full one cannot run).

  a) Full, single-threaded build
  stockfish-19-single.js
    sha256 72772f8bdd7353e4e24245d946bb831f56bcccf02fa16a779c1b92a6c00e5cc2
  stockfish-19-single.wasm
    sha256 8725c26572762617fd96b2ea83ff130e6640b85815890d682bf8c49db0820721
  Embedded neural network: nn-1a298aa575a0.nnue (the default network of
  Stockfish 19)

  b) Lite, single-threaded build
  stockfish-19-lite-single.js
    sha256 d3344124ab067fb0b90ee77873bb8e9fbf5fc01bc525fe714b0f942581e889e6
  stockfish-19-lite-single.wasm
    sha256 57ac2d72312aba346760e3f173f687a8c211208e97a87268436f7f0e10bb5387
  Embedded neural network: nn-61e7af4bb97d.nnue (the 1 MB "lite" network
  by sscg13, https://github.com/sscg13/Stockfish/tree/sf19-1mb)

CORRESPONDING SOURCE (GPLv3 section 6(d)): the complete source code used to
build these files - the Stockfish C++ sources (including the lite-network
code), the Makefile and the Emscripten build script - is in the upstream
repository at the exact commit that published them:

  Repository: https://github.com/nmrugg/stockfish.js
  Commit:     9cb3e5066d48f1a35d792afeda36eff37ae60570 (tag v19.0.0, "Stockfish.js 19")
  Browse:     https://github.com/nmrugg/stockfish.js/tree/9cb3e5066d48f1a35d792afeda36eff37ae60570
  Download:   https://github.com/nmrugg/stockfish.js/archive/9cb3e5066d48f1a35d792afeda36eff37ae60570.tar.gz
  Upstream engine: https://github.com/official-stockfish/Stockfish (tag sf_19)

The two neural networks are not stored in that repository; the build
downloads them by name. They are available, unmodified, from the Stockfish
network server:
  https://tests.stockfishchess.org/api/nn/nn-1a298aa575a0.nnue
  https://tests.stockfishchess.org/api/nn/nn-61e7af4bb97d.nnue

If any of these links stops working, write to albanofrancesco22@libero.it
and we will send you the same source code and networks, free of charge (or
at no more than the cost of physically performing the transfer), for as long
as we serve these files and in any case for at least three years after we
last serve them.

2) OTHER ENGINE BUILDS
----------------------
None. Only the four files listed in 1) are served under /stockfish/.

NEURAL NETWORKS
---------------
The NNUE network files are distributed by the Stockfish project (and, for the
lite network, its author) together with the engine source and are embedded
in the GPLv3 engine builds; we redistribute them unmodified, as part of the
engine, under the same terms. Network catalogue:
https://tests.stockfishchess.org/nns

TRADEMARK
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"Stockfish" is the name of the Stockfish project. ChessNotes is not
affiliated with or endorsed by the Stockfish project or by Chess.com, LLC.