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#17 in Game engines

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Pleco is a Chess Library, containing the building blocks of the chess engine Stockfish, re-written entirely in Rust.

Pleco crate Build Status

This project is split into two crates, pleco (the library you are currently in), which contains the library functionality, and pleco_engine, which contains the UCI (Universal Chess Interface) compatible Engine & AI.

The overall goal of pleco is to recreate the Stockfish engine in rust, for comparison and educational purposes. As such, the majority of the algorithms used here are a direct port of Stockfish's, and the credit for the majority of the code go directly to the maintainers and authors of Stockfish.

For the chess engine implemented using this library provided by pleco, see pleco_engine.


Some of the features pleco implements:

  • Bitboard Representation of Piece Locations:
  • Ability for concurrent Board State access, for use by parallel searchers
  • Full Move-generation Capabilities, including generation of pseudo-legal moves
  • Statically computed lookup-tables (including Magic Bitboards)
  • Zobrist Hashing
  • A Transposition Table: lightning fast lookup table storing information for a board
  • Pre-implemented searchers, some of which using rayon.rs for easy parallelism


To use Pleco inside your own Rust projects, Pleco.rs is available as a library on crates.io. nightly rust is required to use.

Basic Usage

Setting up a board position is extremely simple.

use pleco::{Board,Player,PieceType};

let board = Board::start_pos();
assert_eq!(board.count_piece(Player::White,PieceType::P), 8);
assert_eq!(&board.fen(),"rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1");

Creating a board from a Position

A Board can be created with any valid chess position using a valid FEN (Forsyth-Edwards Notation) String. Check out the Wikipedia article for more information on FEN Strings and their format.

let board: Board = Board::from_fen("rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq c6 0 2").unwrap();

Applying and Generating Moves

Moves are represented with a BitMove structure. They must be generated by a Board object directly, to be considered a valid move. Using Board::generate_moves() will generate all legal BitMoves of the current position for the current player.

use pleco::{Board,BitMove};

let mut board = Board::start_pos(); // create a board of the starting position
let moves = board.generate_moves(); // generate all possible legal moves
assert_eq!(board.moves_played(), 1);

We can ask the Board to apply a move to itself from a string. This string must follow the format of a standard UCI Move, in the format [src_sq][dst_sq][promo]. E.g., moving a piece from A1 to B3 would have a uci string of "a1b3", while promoting a pawn would look something like "e7e81". If the board is supplied a UCI move that is either incorrectly formatted or illegal, false shall be returned.

let mut board = Board::start_pos(); // create a board of the starting position
let success = board.apply_uci_move("e7e8q"); // apply a move where piece on e7 -> eq, promotes to queen
assert!(!success); // Wrong, not a valid move for the starting position

Undoing Moves

We can revert to the previous chessboard state with a simple Board::undo_move():

let mut board = Board::start_pos();
board.apply_uci_move("e2e4"); // A very good starting move, might I say


Any and all contributions are welcome! Open up a PR to contribute some improvements. Look at the Issues tab to see what needs some help.


Pleco is distributed under the terms of the MIT license. See LICENSE-MIT for details. Opening a pull requests is assumed to signal agreement with these licensing terms.

MIT license


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