chess

Topics: chess, chess-engine, rust, uci, cli

A multi-crate Rust chess engine with CLI interface.

Live demo: https://hieudoanm.github.io/chess/

Structure

chess/
  Cargo.toml          # Workspace root
  crates/
    core/             # chess-core: board, pieces, move generation, rules
    engine/           # chess-engine: negamax search with alpha-beta pruning
    cli/              # chess-cli: command-line interface

Crates

chess-core

Core chess types and logic:

• Board - Board representation with FEN support
• Position - Game state (side to move, castling rights, en passant, clocks)
• Piece / PieceType / Color - Chess piece types and colors
• Square - Board square representation with SAN notation
• Move / MoveType - Move representation including promotions and castling
• Move generation with legality filtering (no moves that leave king in check)
• Check detection, checkmate, stalemate detection

chess-engine

Engine search:

• Negamax algorithm with alpha-beta pruning
• Material-based evaluation
• Configurable search depth

chess-cli

Command-line interface:

• chess board - Display starting FEN
• chess moves - List all legal moves from start
• chess play --depth 3 - Interactive play mode with engine recommendations
• chess uci - UCI protocol mode (reads commands from stdin)

UCI protocol

The engine speaks the standard UCI protocol. Run chess uci and send commands:

uci
isready
position startpos moves e2e4 e7e5
go depth 3
bestmove g1f3
quit

MCP server

The engine exposes an MCP (Model Context Protocol) server over stdio JSON-RPC, built into the chess binary:

cargo run -p chess-cli -- mcp

# then send MCP messages to stdin, e.g.:
{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}
{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}
{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"get_board","arguments":{}}}

Available MCP tools:

• new_game - Start a new game
• get_board - Get current board (ASCII + FEN)
• get_legal_moves - List legal moves (UCI)
• make_move - Play a move (UCI notation)
• get_best_move - Engine's best move at a depth

Available MCP resources:

• chess://board - Current board state

Benchmark

Run cargo run -p chess-cli -- bench to benchmark move generation (perft) from the starting position:

cargo run -p chess-cli -- bench

Reports node counts at depths 1-5, ns/node, and total nodes/second. Depths 1-3 match the published perft values for the initial position (20, 400, 8902).

Supported UCI commands: uci, isready, ucinewgame, position (startpos/fen + moves), go (depth, wtime, btime, winc, binc, nodes, mate, infinite), stop, quit.

Get Started

One-command install (prebuilt binary, or builds from source via cargo):

curl -fsSL https://raw.githubusercontent.com/hieudoanm/chess/master/scripts/install.sh | sh

Or build from source:

cargo build --release

Usage

# Build
cargo build --release

# View starting position
cargo run -p chess-cli -- board

# List legal opening moves
cargo run -p chess-cli -- moves

# Interactive play
cargo run -p chess-cli -- play --depth 3

Testing

cargo test

Top Chess Engines (CCRL 40/15, Oct 2026)

Rank	Engine	CCRL 40/15	Type	Licence	GitHub	Notes
1	Stockfish 19	3650	NNUE	GPL-3.0	GitHub	Strongest engine, TCEC champion
2	Reckless 0.9.0	3644	NNUE	AGPL-3.0	GitHub	Written in Rust
3	PlentyChess 7.0.0	3642	NNUE	GPL-3.0	GitHub
4	pawnocchio 2.0.1	3641	NNUE	GPL-3.0	GitHub
5	Torch v4d	3639	Neural net	Private		Chess.com
6	Coda 0.9.4	3638	NNUE	GPL-3.0	GitHub
7	Integral v8	3638	NNUE	None	GitHub	Free download
8	Cinder 0.6.1	3637	NNUE	GPL-3.0	GitHub
9	Obsidian 16.0

Lc0 (Leela Chess Zero) is also among the strongest, especially with GPU support (CCRL FRC: ~4080 on RTX 5050).

• Lc0 GitHub

Sources: Rama Chess, CCI Ratings

License

This project is licensed under the MIT License.