Archduchess

A UCI chess engine written from scratch in C++. Hosted on GCP and rated ~2000 on Lichess.

Play against Archduchess on Lichess!

Building the Project

This project uses CMake

Prerequisites

• CMake >= 3.30
• A C++20 compatible compiler (e.g., GCC, Clang, MSVC)

Build Types

• Release: Optimized for speed, disables debug info.
• Debug: No optimizations, includes debug symbols, extra warnings.
• Profile: Optimized for profiling, disables PIE, enables profiling flags.

Option 1: Fast build

From the root folder

sh build.sh

The script accepts the following parameters:

Parameter	Description	Default
release / debug / profile	Choose build preset	release
--test	Run tests after building	false
--clean	Delete the build directory before configuring and building	false

Option 2: Build step by step

From the root folder

1. Configure the project:

   cmake --preset <configure-preset-name>

   Replace <configure-preset-name> with one of

   • ninja-release
   • ninja-debug
   • ninja-profile

2. Build the project:

   cmake --build --preset <build-preset-name>

   Replace <build-preset-name> with one of

   • release
   • debug
   • profile

   It has to match what you have chosen at step 1

3. (optional) Run the tests:

   ctest --preset <test-preset-name> --output-on-failure

   Replace <test-preset-name> with one of

   • release
   • debug
   • profile

   It has to match what you have chosen at step 1 and step 2

Result

The engine executable will be in build/<build-type>/bin/archduchess.exe

Features

UCI Interface

• uci, isready, ucinewgame, position, go, stop, and quit commands
• go ponder, go searchmoves and go mate are not implemented

Move Generation

• Board representation using bitboards
• Bitboard shift for pawns
• Bitboard masks for knights and kings
• Magic bitboards for sliding pieces
• Generate pseudo-legal moves, then remove illegal moves

Evaluation

• Material count
• Piece-Square Tables

Search

• Negamax
• Alpha-Beta Pruning
• Iterative Deepening
• Aspiration Windows
• Transposition Table
• Quiescence Search
  • Delta Pruning
• Null Move Pruning
• Check Extension
• Late Move Reduction

Move Ordering

• Best move from the previous iteration
• Hash move from the transposition table
• MVV-LVA
• 2 Killer Moves
• History Heuristic
  • Indexed by side to move, start square and end square

Future Roadmap

• Better evaluation (pawn structure, king safety, endgame piece-square tables, etc...)
• Static Exchange Evaluation
• Late Move Reduction

Helpful Resources

• The Chess Programming Wiki
• TalkChess Forum
• Cute Chess
• Stockfish Features List