Open-Source Licences & Credits

Rama Chess is built on the work of many people. This page names them: the chess engines and their source code, the neural networks, the 3D chess sets and their artists, the puzzle data, the piece sets, the libraries and the fonts. It covers the website, the Android app, the iPhone app and the Windows app.

Chess engines

Every chess engine in Rama Chess is open-source software, used under its own licence with credit to its authors. The search and evaluation are the authors’ work. Where we changed an engine so it runs in a browser or on a phone (a small input/output bridge, or loading the network from a file), the change is published next to the source. Source is the complete source code of the version we build, hosted on ramachess.com; our change is the exact patch; build notes lists the upstream tag and commit, the flags and the network.

Where: W = website, A = Android app, i = iPhone app, Win = Windows app.

The same list with download sizes is on Open-source chess engines, and the engines you can play in the browser are explained one by one on Chess engine licences & source code. Bundled third-party code inside the engines keeps its own licence: Fathom and Pyrrhic Syzygy probing (MIT), incbin (Unlicense), fmt (MIT), the zstd decoder (BSD) and SIMDe (MIT), as listed in each engine’s build notes.

Independent project. Rama Chess is not affiliated with, endorsed by or sponsored by the authors of these engines. Engine names are used only to say which engine you are playing.

Neural networks

Most engines use a neural network file (NNUE). We use each engine’s own default network, unchanged, downloaded from ramachess.com. The licence is written as its author states it; where the author states none, we say so.

Ethereal, Laser, Rodent IV and Weiss use classical (hand-written) evaluation and need no network file. Lc0 on Android has its network built into the official program.

3D boards & pieces

The 3D chess sets are made by independent artists and shared on Sketchfab under the Creative Commons Attribution 4.0 licence (CC BY 4.0). We split each model into pieces; in the app every set uses our own board and materials, and on the website the textures are removed and some shapes simplified. Thank you to every artist. More detail: 3D set credits.

Homepage 3D board: the model is “Chess Set” by Riley Queen on Poly Haven, public domain (CC0), compressed for the web. It is drawn with three.js.

Piece sets

• Merida by Armando Hernandez Marroquin, as distributed by lichess.org — GNU GPL version 2 or later.
• Rama — derived from Merida (new fills, outline and gold collar line by Rama Chess) — GNU GPL version 2 or later.
• Rama Bold, Rama Classic, Rama Modern, Rama Royal — original designs made by Rama Chess.

Puzzles & data

• Puzzles: the Lichess puzzle database, released into the public domain (CC0). Thank you to lichess.org and its players.
• Leela policy table: Lc0’s list of the 1858 policy moves, as published in a0lite-js by sad-pixel — MIT.

Libraries & fonts

Credits being checked

We are still confirming the authors and licences of these items. This list will be completed:

• The extra 2D piece sets in the website’s board settings (Alpha, California, Cardinal, CBurnett, Fresca, Gioco, Maestro, Pirouetti, Staunty, Tatiana, Wikipedia).
• The wood veneer textures (walnut and white maple) of the homepage 3D board.

If you made one of these and want a different credit, or want it removed, please write to us.

Source code requests

For every GPL or AGPL program in Rama Chess you can get the complete corresponding source code, including our changes. Most of it is linked above. For anything marked “source on request”, or if you want any source in another way, write to:

[email protected]

We send the complete source code of that program. This offer is valid for at least three years after we last distributed that version.

Last updated 13 November 2026. See also About · Terms of service · Privacy policy.