Ekagine Chess Engine

Ekagine is a Rust chess engine that speaks the UCI protocol and focuses on strong tactical play powered by NNUE evaluation and a modern alpha-beta search stack. The code base is organized for experimentation and includes the same core techniques used by contemporary tournament engines.

The engine is not yet tested or ranked on ccrl, but I estimate it to be more or less 2800 elo

If you already have a lichess account, you can challenge it online at: https://lichess.org/@/ekagine.

Features

• UCI-compliant command loop with option negotiation (Threads) and self-identification for GUI integration.
• Iterative deepening with aspiration windows, principal-variation tracking, and info-string logging hooks for debugging.
• Negamax alpha-beta search featuring:
  • Transposition table with aging and bound-aware probing.
  • Killer moves, history, and correction-history heuristics for quiet move ordering.
  • Late move reductions, late move pruning, static exchange pruning, and futility variants (regular/reverse) to trim the tree.
  • Null-move pruning with adaptive depth reduction and check/passed-pawn extensions.
• Correction history system that captures evaluation deltas to suppress repeatedly over-valued quiet moves.
• NNUE incremental evaluation pipeline (driven by net.bin) with stack-based state push/pop so the network is coherently updated through the search.
• Incremental move generator with phased ordering (TT move, MVV-LVA captures, killer quiets, high-scoring quiets, remaining captures/quiets).
• Time-plan manager tuned for practical time controls (movetime, wtime/btime, increments, infinite, ponder) that tracks previous think time.
• Testing harness with unit coverage for NNUE deltas and move ordering helpers.

Requirements

• Rust toolchain (stable rustc/cargo). Install from https://rustup.rs/ if needed.
• The bundled net.bin holds the pretrained NNUE weights used during search. Replace it with another network of the same architecture if you want to experiment with different training data.

Building

cargo build --release

Artifacts will appear under target/release/. The engine binary is named chess_engine by default.

Running

To run the engine in a UCI shell:

cargo run --release

Then enter standard UCI commands such as uci, isready, position, and go. Connect the binary to any UCI-compatible GUI (e.g. CuteChess, Arena, Banksia) to play games.

Testing

cargo test

Continuous testing is handled on a custom SPRT infrastructure at https://ssprt.ekazuki.fr (read-only access). Each pull request triggers a GitHub Action that dispatches games to that cluster automatically.