ChessRealms.Engine

ChessRealms.Engine is a .NET 10 library for standard chess positions and legal play. It uses bitboards and magic attack tables for move generation. The public ChessGame API supports FEN import/export, legal moves, promotion, history and undo, and standard checkmate, stalemate and supported draw rules. The repository also includes tests, a console game, a perft runner, benchmarks and a magic-number search tool.

It does not provide an AI/search engine, UCI, SAN/PGN, Chess960 or tournament services such as clocks and draw agreements. Dead-position recognition is deliberately incomplete; see the game API guide for the exact boundary.

Build and test

Install the .NET SDK version pinned in global.json and run from the repository root:

dotnet restore ChessRealms.Engine.slnx --locked-mode
dotnet build ChessRealms.Engine.slnx -c Release --no-restore
dotnet test ChessRealms.Engine.slnx -c Release --no-build --filter "TestCategory!=Deep"
dotnet pack src/ChessRealms.Engine/ChessRealms.Engine.csproj -c Release --no-build

The Deep test category contains slower perft cases and is opt-in. See the contribution guide for contributor checks.

Public API

using System;
using ChessRealms.Engine;

var game = new ChessGame();
var branch = game.Clone();
var result = branch.MakeMove(CoordinateMove.Parse("e2e4"));

if (result != MoveResult.None)
{
    Console.WriteLine(branch.ToFen());
    ChessPiece piece = branch.GetPiece(Square.Parse("e4"));
    branch.UndoMove();
}

ChessGame is mutable: use Clone() for an independent branch. Coordinate promotions require a suffix such as a7a8q. The game API guide describes ownership, FEN validation, draw claims, repetition and supported rule boundaries.

The package intentionally exposes only the high-level types in the ChessRealms.Engine namespace. Bitboards, encoded moves, magic tables, raw positions and repository tools are implementation details and may change without becoming package contracts.