Leela Chess Zero

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Original author(s)	Gian-Carlo Pascutto, Gary Linscott
Developer(s)	Gary Linscott, Alexander Lyashuk, Folkert Huizinga, others
Initial release	9 January 2018; 6 years ago (2018-01-09)
Stable release	v0.30 / 21 July 2023; 10 months ago (2023-07-21)
Repository	github.com/LeelaChessZero/lc0
Written in	C++
Operating system	Windows, Mac, Linux, Ubuntu, Android
Type	Chess engine
License	GPL-3.0-or-later
Website	lczero.org

This article is part of the series on
Chess programming
Board representations 0x88 Bitboards
Evaluation functions Deep neural networks (Transformers) Attention Efficiently updatable neural networks Handcrafted evaluation functions Piece-square tables Reinforcement learning Stochastic gradient descent Supervised learning Texel tuning Unsupervised learning
Graph and tree search algorithms Minimax Alpha-beta pruning Principal variation search Quiescence search Monte Carlo tree search
Chess computers Belle ChessMachine ChipTest Cray Blitz Deep Blue Deep Thought HiTech Hydra Mephisto Saitek
Chess engines AlphaZero Chess Tiger Crafty CuckooChess Deep Fritz Dragon by Komodo Chess Fairy-Max Fritz Fruit GNU Chess HIARCS Houdini Ikarus Junior KnightCap Komodo Leela Chess Zero MChess Pro Mittens MuZero Naum REBEL Rybka Shredder Sjeng SmarThink Stockfish Torch Turochamp Zappa
v t e

Leela Chess Zero (abbreviated as LCZero, lc0) is a free, open-source, and deep neural network–based chess engine and volunteer computing project. Development has been spearheaded by programmer Gary Linscott, who is also a developer for the Stockfish chess engine. Leela Chess Zero was adapted from the Leela Zero Go engine,^[1] which in turn was based on Google's AlphaGo Zero project.^[2] One of the purposes of Leela Chess Zero was to verify the methods in the AlphaZero paper as applied to the game of chess.

Like Leela Zero and AlphaGo Zero, Leela Chess Zero starts with no intrinsic chess-specific knowledge other than the basic rules of the game.^[1] Leela Chess Zero then learns how to play chess by reinforcement learning from repeated self-play, using a distributed computing network coordinated at the Leela Chess Zero website.

As of April 2024^[update], Leela Chess Zero has played over 2.5 billion games against itself, playing around 1 million games every day,^[3] and is capable of play at a level that is comparable with Stockfish, the leading conventional chess program.^[4][5]