Mimir

Mimir is a UCI compatible chess engine built from scratch.

Features

• Bitboard move generation (legal & pseudo-legal) verified with perft tests.
• Full compliance of drawing rules: Insufficient material, three-fold-repetition, and 50 move rule.
• Negamax alpha-beta pruning with iterative deepening depth first search and quiescence search to counter horizon effects.
• Transposition tables with zobrist hashing.
• A classical PST tapered evaluation function optimized by Texel's tuning.
• Modern NNUE based evaluation based on 768 perspective architechture with incremental updates.
• Move ordering via hash moves from transposition tables, Most Valuable Victim - Least Valuable Aggressor (MVV-LVA) for captures.
• Killer moves and history heuristics for quiet moves.
• Principal variation search (PVS) with aspiration windows.
• Null move pruning (NMP) and Late move reductions (LMR)
• Reverse Futility Pruning (RFP)
• Delta pruning and Static Exchange Evaluation (SEE).
• A UCI compatible interface with a soft-hard limit time scheduler.
• Playable on lichess @playmimir. Uses the lichess bot API.

Building

Requirements

• Rust 1.70+ (for #![feature(variant_count)])
• Standard build tools (cargo)

Building and Testing

cargo build --release

# Run all tests
cargo test --release

References

• Chess Programming Wiki – comprehensive reference for most techniques outlined above
• lichess-bot - A bridge between lichess and bots.
• beans.bin - Credits to @ciekce [Stormphrax] from discord for training the network