Stockfish.js 19.0.1 by Nathan Rugg, Chess.com and the Stockfish contributors. Unmodified lite single-threaded WebAssembly engine, running in a separate browser worker. Licensed under GNU GPL v3.
GPL v3 license · Corresponding source and build scripts · Pinned upstream source
Browser rules: chess.js 1.4.0 by Jeff Hlywa and contributors, BSD-2-Clause. License. Server rules: p-chess/chess 1.2.0, MIT. License.
The 26 computer levels combine beginner random-move probabilities with Stockfish skill settings and thinking time. They are not certified Elo ratings. Level 26 is this game’s strongest configuration, using the lite engine and a short search budget.
The 2D fantasy set uses original Phakbet characters adapted into generated chess figurines. The 3D fantasy and classic sets are original procedural solid models with articulated character limbs. Classic 2D mode uses standard chess symbols rendered by the browser.
Three.js 0.186.1, MIT. Three.js license. The dragon and bunny models are original Phakbet designs.
Battle sounds are original procedural Web Audio synthesis: footsteps, dragon growls, metal strikes and cartoon bunny voices. No recorded character voices or third-party sound samples are included.