Challenger is a UCI-compliant chess engine. Challenger-rs is a re-designed version of the original challenger project that uses Rust and some lessons learned from it's predecessor.
- To "challenge" the Stockfish chess engine, which is currently the best chess engine in the world.
- Have fun.
- Improved understanding of internal chess engine design techniques.
- Learn the Rust Programming Language. (done!)
Currently the project is focused on implementing the uci commands required to be a uci-compliant chess engine. This includes writing the move generation functions, search capabilities, position evaluation, and ensuring challenger can play fully legal chess.
Challenger is a UCI-compliant engine. UCI (The Universal Chess Interface) is a text-based protocol that allows a GUI or other interface to send game commands to the engine.
Challenger uses Bitboards, a popular piece-centric board representation. Using an unsigned, 64-bit integer, the least significant bit represts A1, and the most significant represents H8.
Inspired by from-to based moves as well as Stockfish's move representation, Challenger uses an unsigned 16-bit integer to encode moves with the lower 12 bits representing the origin and destination squares, and the upper 4 bits for encoding special move types.
For efficiency purposes, challenger uses Magic Bitboards to perform lookups on pre-initialized attack tables for sliding pieces. A similar, less complex, set of lookup tables are used for Knights and Kings. Pawns are the only piece type that are generated on the fly due to their relatively simple move patterns.
Current level: 0
Percentage winning next level:
The progress of challenger will be gauged as follows: Challenger will play Stockfish starting at its lowest level. Once the Challenger engine can beat the Stockfish engine at the given level at least 60% of the time, the Stockfish level will be increased, the "Current level completed" label above will be updated, and a release of the code will be made to snapshot the progress made. The "Percentage winning next level" label indicates challenger's progress in beating the next level of Stockfish.
Percentages will be determined by playing 10 games and recording winnings. While this method is not statistically sound, it works well enough for determining when challenger should increase the difficulty level of the Stockfish engine again.
Development for challenger will be done in Rust, using the built-in testing and benchmarking capabilities. Before opening issues or pull requests, please read the contributing page for Challenger.
Contributions of all kinds are welcomed and encouraged. This project is far from finished and there are always portions of the code or documentation that can be improved.
Please read the License for this project.