Chess Game with AI

A fully-featured chess game implemented in C# with GTK# for the graphical interface. Play against an intelligent AI opponent that uses minimax search with alpha-beta pruning and quiescence search.

Features

Complete Chess Rules Implementation

• All standard chess moves: Regular piece movement, captures, castling (kingside and queenside), en passant, and pawn promotion
• Legal move validation: Only legal moves are allowed; the game prevents moves that would leave the king in check
• Check and checkmate detection: Automatic game-ending detection for checkmate and stalemate
• Move history tracking: Full move/unmove system for AI search

AI Opponent

• Minimax algorithm with alpha-beta pruning for efficient search
• Quiescence search to handle tactical positions more accurately
• Move ordering using MVV-LVA (Most Valuable Victim - Least Valuable Aggressor) heuristic
• Position evaluation with piece-square tables for both midgame and endgame
• Configurable search depth (default: 4 ply)
• Material and positional evaluation to guide the AI's decision-making

User Interface

• Visual chess board with alternating light and dark squares
• Piece graphics with proper scaling
• Move highlighting to show available moves for the selected piece
• Win/draw animations to celebrate the game outcome
• Promotion dialog for choosing a piece when a pawn reaches the back rank

Requirements

• .NET 7.0 or higher
• GTK# 3.24.24.95
• Linux, macOS, or Windows with GTK+ installed

Installation

1. Clone this repository:

git clone https://github.com/Keyboris/Chess.git
cd chess

2. Install GTK# dependencies (if not already installed):

   • Linux: sudo apt-get install gtk-sharp3
   • macOS: brew install gtk+3
   • Windows: Download GTK# from gtk.org

3. Build the project:

dotnet build

4. Run the game:

dotnet run

How to Play

1. White (AI) moves first - The AI will automatically make its first move
2. Click on a piece to select it and see available moves (highlighted in blue)
3. Click on a highlighted square to move your piece there
4. Pawn promotion: When your pawn reaches the opposite end, choose which piece to promote to
5. The game ends when checkmate or stalemate occurs

Project Structure

chess/
├── Controller.cs    # Game logic, board state, and move execution
├── Pieces.cs        # Piece classes (Pawn, Knight, Bishop, Rook, Queen, King)
├── agent.cs         # AI implementation with minimax and evaluation
├── view.cs          # GTK# UI components and event handling
├── chess.csproj     # Project configuration
└── pieces/          # PNG images for chess pieces
    ├── white_*.png
    └── black_*.png

Technical Details

AI Search

• Minimax depth: 4 plies (configurable via MaxDepth constant)
• Alpha-beta pruning: Reduces search space significantly
• Quiescence search: Extends search for captures and promotions
• Evaluation function: Combines material value with position-specific bonuses

Chess Rules Implementation

• Castling: Checks for king/rook movement, empty squares, and squares under attack
• En passant: Tracks the last pawn double-move for capture opportunities
• Move generation: Pseudo-legal moves are generated, then filtered for legality
• Check detection: Uses square attack detection to validate king safety

Configuration

You can adjust the AI difficulty by changing the MaxDepth constant in agent.cs:

private const int MaxDepth = 4; // Increase for stronger (but slower) AI

Future Enhancements

• Switch to bitboards model
• Add time controls and chess clock
• Implement transposition tables for faster search
• Add game save/load functionality
• Support for player vs. player mode
• Move history display with notation
• Opening book integration
• Difficulty levels

License

This project is open source and available under the MIT License.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Acknowledgments

• Piece images from standard chess sets
• Chess programming concepts from the Chess Programming Wiki
• GTK# for the cross-platform GUI framework