BitBishop

A modern chess engine written in C++23, built as a learning project around bitboards, move generation, search, and engine architecture.

Overview

BitBishop is a personal project focused on learning by building a real engine. The codebase is organized as a layered architecture with dedicated modules for compile-time geometry, occupancy-aware attacks, legal move generation, reversible move execution, evaluation, search, and a UCI-facing interface.

The goal is not just to "have a chess engine," but to keep the code readable, testable, and well documented for anyone curious about chess programming or modern C++.

Current State

• UCI executable via bitbishop with uci, isready, ucinewgame, position, go, stop, and quit
• FEN parsing and UCI move parsing
• Legal move generation with checks, pins, castling, en passant, and promotions
• Reversible move execution with position history and Zobrist hashing
• Basic evaluation using material and piece-square tables
• Negamax search with alpha-beta pruning and quiescence search
• Perft tooling and a tiered GoogleTest suite
• CMake Presets, vcpkg integration, linting hooks, and coverage targets

BitBishop is already usable for development and basic UCI-driven experiments, but it is still under active development. The UCI layer exists today, though protocol coverage and search strength are not yet "finished engine" level.

Short-Term Focus

• stronger search features and move ordering
• richer UCI support and time-control handling
• continued validation with perft and targeted tests
• ongoing documentation improvements across the codebase

Getting Started

Prerequisites

• CMake 3.27 or newer
• Clang on Unix-like systems, or MSVC 2022 on Windows
• vcpkg with VCPKG_ROOT configured
• Ninja on Unix-like systems, or Visual Studio 2022 on Windows

Optional developer tools:

• clang-format (code formatting)
• clang-tidy (code linting)
• llvm-cov (code coverage)
• llvm-profdata (code coverage)

Build and Test

Typical Unix-like workflow:

cmake --preset clang_debug
cmake --build --preset clang_debug
ctest --preset quick-validation-clang-debug

Typical Windows workflow:

cmake --preset msvc_debug
cmake --build --preset msvc_debug
ctest --preset quick-validation-msvc-debug

The project uses CMake Presets for configure, build, and test workflows. For the full preset matrix, coverage targets, and packaging notes, see the CMake guide.

Run the Engine

On Unix-like systems, the executable is typically produced under the selected build preset directory:

./build/clang_debug/main/bitbishop

Minimal UCI smoke test:

uci
isready
position startpos moves e2e4 e7e5
go depth 4
quit

For more information about available commands, see this doc.

Documentation

Project Docs

Guides

• Engine commands (UCI and extensions)
• Build the project with CMake
• Run CI on GitHub
• Internal architecture
• Debug with perft

Memos

• FEN notation memo
• UCI protocol memo

External References

• Andrew Healey - Building My Own Chess Engine
• Chess Programming Wiki
• UCI overview on Chessprogramming

Project Structure

BitBishop/
├── build/                       # Build artifacts
├── cmake/                       # CMake helper scripts
├── docs/                        # Documentation and guides
├── include/bitbishop/           # Public headers and architecture docs
├── main/                        # Executable entrypoints
├── src/bitbishop/               # Library sources
├── tests/bitbishop/             # Unit and validation tests
├── CMakeLists.txt               # Build configuration
├── CMakePresets.json            # Preset-based workflows
├── vcpkg.json                   # Dependency manifest
└── ...

For a more detailed view of the engine layers, see include/bitbishop/readme.md.

Design Goals

• Learn and demonstrate low-level C++ techniques through a real project
• Keep the architecture explicit and easy to navigate
• Maintain strong test feedback with tiered validation
• Document the reasoning behind the implementation, not just the APIs

Contributing

This is primarily a personal learning project, but suggestions and constructive feedback are welcome.

Before opening a pull request, please read:

• CONTRIBUTING.md
• CODE_OF_CONDUCT.md
• SECURITY.md

Feel free to:

• Open issues for bugs or suggestions
• Submit pull requests with improvements
• Share your own learning experiences

Note

This is a personal project for now. Community documentation has been written in case one day, someone wants to contribute.

Status

BitBishop is functional enough for development, experimentation, and basic UCI-based testing, but it is still an in-progress engine rather than a polished competitive one.

License

• MIT License

Acknowledgments

This project draws heavily from the chess programming community and the many people who document engine design in public.

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Repository: github.com/Hardcode3/BitBishop