Lib.rs

haitaka ハイタカ

Rust Shogi move generation library

haitaka is a Shogi move generation library written in Rust that aims to support fast move generation. It is inspired by the beautifully designed cozy-chess library written by analog-hors. The layout of the modules and the overall design is largely the same as in cozy-chess. Many low-level functions were copied from cozy-chess, with only trivial modifications, but since there are significant differences between Shogi and International Chess, I also modified some of the higher-level functions and added extra functionality.

Name

"Haitaka" or "taka" means "sparrowhawk" in Japanese. "Taka" is a haiku kigo (season word) associated with winter.

   鷹の眼​にこぼれて雁のたち騒ぐ
   Taka no me ni koborete kari no tachisawagu

   ​Escaping the hawk's eye,
   the wild geese
   rise in tumult.
   -— 加賀千代女 (Kaga no Chiyojo)

Overview

• no_std compatible
• Strongly-typed API that makes heavy use of newtypes to avoid errors
• Efficient bitboard-based board representation
• Performant legal move generation
• Incrementally updated zobrist hash for quickly obtaining a hash of a board
• Supporting both Magic Bitboards and the Qugiy algorithm for slider move generation
• Support for parsing SFEN strings

Main differences with cozy-chess

• BitBoard uses u128 instead of u64 as backing to handle the 9x9 Shogi board
• Move generation handles both board moves and drops
• Move generation of sliders also implements the Qugiy algorithm
• File-major ordering of squares to make move generation faster

Crate features

• std: Enable features that require std. Currently only used for the Error trait.

Installation

Add haitaka to your Cargo.toml:

[dependencies]
haitaka = "0.2.0"   # or use the latest version on crates.io

Usage

Basic

use haitaka::*;
// Start position
let board = Board::startpos();
let mut move_list = Vec::new();
board.generate_moves(|moves| {
    // Unpack into move list
    move_list.extend(moves);
    false
});
assert_eq!(move_list.len(), 30);

Perft

cargo run --release --example perft -- 5

Testing

This code has been tested on an Apple M2, using the stable-aarch64-apple-darwin toolchain. In GitHub workflows it has also been tested on Ubuntu.

The code has not yet been stress tested yet or used in an actual Shogi engine.

To run all tests use:

cargo test

Acknowledgments

Portions of this library are derived from the cozy-chess project by analog-hors. The cozy-chess project is licensed under the MIT license, and its license text is included in this repository under third_party/cozy-chess/LICENSE.

References

• cozy-chess
• WCSC31 Qugiy Appeal
• Qugiy in YaneuraOu
• USI - Universal Shogi Interface
• YaneuraOu