Chess Bot

A C# chess engine built with bitboards and accessible via a REST API.

Try it: Chess Bot

---

Current Features

Core Engine

• Bitboard Board Representation
• Magic Bitboards
• Legal Move Generation
• *Opening Book
• Repetition Detection

Search

• Alpha-Beta Pruning
• Transposition Tables
• Move Ordering
• PVS
• Mate Search
• Asperation Windows
• Null Move Search
• Itterative deeping
• Quiescence Search

Evaluation

• Material Evaluation
• Piece-Square Tables
• Pawn Structure

---

Elo Speculation

Based on current implementation, I estimate the bot to play at approximately 1600-1900 Elo. This is an informal estimate.

---

Usage

Prerequisites

• .NET 10.0 SDK or later

Building & Running

1. Clone the repository:

   git clone https://github.com/RJDonnison/ChessBot.git
   cd ChessBot

2. Run the API server:

   dotnet run --project ChessBot.Api

   The API will start on http://localhost:5000

Testing with a UI

To test without building a custom UI, you can use the provided Chess Bot Interface.

API Endpoints

GET /bestmove

Returns the best move for a given position.

Parameters:

• fen (required) - The board position in FEN notation

Example:

curl "http://localhost:5000/bestmove?fen=rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR%20w%20KQkq%20-%200%201"

Response:

{
  "bestmove": "e2e4"
}

Integration Example

// Import the ChessBot.Core library
using ChessBot.Core;

var bot = new Bot();
string fen = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
string bestMove = bot.GetBestMove(fen);
Console.WriteLine($"Best move: {bestMove}");

---

Project Structure

• ChessBot.Core - Core engine logic
• ChessBot.Api - ASP.NET API wrapper
• ChessBot.Core.Tests - Unit tests for Perft move generation tests

---

Future Features (Roadmap)

• WebAssembly (WASM) - Browser-native engine compilation
• Multi-threading - Parallel search implementation
• ML evaluation - Neural network-based position evaluation
• History heuristic - Move ordering improvement using historical data
• King safety evaluation - Enhanced king attack detection and safety scoring
• Lazy evaluation - Deferred evaluation for performance

---

License

See LICENSE for details.