Open Source C++ Chess Engines

Stockfish is a free, powerful UCI chess engine derived from Glaurung 2.1. Stockfish is not a complete chess program and requires a UCI-compatible graphical user interface (GUI) (e.g. XBoard with PolyGlot, Scid, Cute Chess, eboard, Arena, Sigma Chess, Shredder, Chess Partner or Fritz) in order to be used comfortably. Read the documentation for your GUI of choice for information about how to use Stockfish with it. Stockfish is a 11-time winner of the Top Chess Engine Championship. Stockfish is open source (GPLv3 license). That means you can read the code, modify it, and contribute back. You can use Stockfish on your computer or on your iOS or Android device. So you can get world-class chess analysis, wherever you are. The Stockfish engine features two evaluation functions for chess, the classical evaluation based on handcrafted terms, and the NNUE evaluation based on efficiently updatable neural networks.

Chess engine code name "Gull"

Cassandre is an extensible chess engine written in C++, it is Winboard/XBoard compliant.

Provides interface for working with chess games in PGN (use libpgn) make moves, and get result

Redqueen is an UCI (Universal Chess Interface) only compatible chess engine written in C++.

A powerful chess engine written in C++. It currently implements hybrid board representation, alphabeta pruning, quiescence search, static evaluation, legal move generator, iterative deepening, MVV/LVA move reordering, makemove, unmakemove and uci move representation standard, tapered evaluation. Elostat gives the current version an ELO of 2100 measured over 50 games.

Grapefruit is an opensource chess engine based on Toga II 1.4 beta5c.

Kenny is a Winboard/XBoard chess engine based on Winglet (http://www.sluijten.com/winglet/source/index.htm), an open source chess program. Winglet's full source code can be obtained from Winglet. Kenny is an advanced form of Winglet which plays better at some faster time levels like blitz chess or upto 20 minute games, but almost always loses against Winglet when the time controls are 40 minutes or more for each. These tests were run by setting up various tournamennts on the free Chess GUI Arena Version 3.0. Kenny uses modified values for evaluation of various parameters, thus introducing almost an entirely new engine, because the evaluation function is the heart of a chess engine.

Slibo is a chess interface and a chess engine for KDE.

OliveChess is a simple chess engine compatible with modern chess interfaces such as ChessBase products, Arena and XBoard/Winboard. The engine supports UCI and XBoard protocols. Note: in order to use it as an xboard engine you may need Polyglot tool to be installed first

A CECP (glChess-, xboard-, ...- compatible) chess engine specially conceived as a study application of Belief-Desire-Intention AI Architectures.

A simple attempt at a chess program, written in C++. Originally it will be for Win32, but with a few adjustments should compile under any environment. This is primarily a learning project for the author, and any help would be appreciated!

Braincrack is a chess engine I wrote in my high school time. It is capable of being used with the Winboard protocol and via Winboard->UCI conversion tools within professional chess GUIs like Chessbase.

Brainless is a winboard/xboard chess engine developed in C++.

This is an easy to use chess engine written in C++ with a very simple interface

CINAG is an UCI computer chess engine. This is a module which thinks about the game and try to find the best move for each position. Our goal is to create a quite strong opponent by using state of the art AI technics.

Chesley is a free software chess engine written in C++ targeting Windows and Unix-like platforms and the xboard GUI. Chesley implements a number of modern chess programming techniques, including bitboard move generation, transposition tables, etc.

Yet another chess engine.

KCChess -- yet another xboard-compatible chess engine.

KMT Chess is a chess engine. It supports Winboard Chess Engine Protocol and can be used in combination with Winboard or Arena user interfaces. KMTWinboard package includes WinboardX interface and a opening book, providing a much better user experience.

MinkoChess is a multiplatform chess engine written in C++.

This project works to match a simple chess engine with an intuitive GUI. The ideal end result can be deployed on decrepit PCs and teach chess wordlessly, through "doing", as it were. With any luck, OpenGambit will reach that point.

PGN reader is a Open Source Chess game interface with emphasis on the study of Chess theory and support for traditional Chess notation forms ( FEN, PGN, Agebraic Notation )and modern non proprietary output formats ( XHTML, XML ). It has been tested on Linux and relies on Qt 4.0 and is being developed with the KDevelop IDE in C++. PGN Reader was born out of a general dissatisfaction with available Chess interfaces and as such presents a unique feature set which emphsizes the study of Chess and traditional Chess notation forms as well as embracing the Open Source philosophy non proprietary culture of the Chess community. Some of the notable features are. Forsythe Edwards Notation. PGN Files read and write. Unadorned Chess Diagrams. Unlimited Simultaneous Diagrams. Diagram Cloning. Graphical Diagramming. XML output for Chess Authoring. PGN processing sub processes. Open Source Chess Engine interfacing.

Purple Haze Chess Engine. Moved to GitHub: https://github.com/vinc/purplehaze

Computer chess engine written using Qt4, which works under Knights, Jose, Arena and other chess board GUI games. Uses bitboard game representation and alpha beta brute-force search to analyse chess positions.