A downloadable game for Windows

Chess Buddy is a desktop chess game with a built-in AI coach powered by Claude. Play against Stockfish at any skill level — from absolute beginner to master — while getting real-time commentary and strategic advice as you play.

Features

  • Play vs. Stockfish at adjustable difficulty (Beginner → Master), with ELO-adaptive mode that matches your skill level automatically
  • AI Coach — ask your coach questions about any position mid-game, get live move commentary streamed as you play, and receive a summary at the end of each game
  • Opening Book — 4,000+ openings from the Lichess ECO database, with opening names, hover tooltips, and suggested main-line continuations
  • Evaluation Bar — real-time Stockfish position evaluation so you always know who's better
  • Move History & Branching — browse back through any game and play alternate lines from any position
  • 2D & 3D Board — toggle between a classic 2D board and a 3D view; fullscreen 3D mode hides the UI for a distraction-free experience
  • Configurable Commentary — set the coach to annotate your moves, the engine's moves, all moves, or none
  • Pawn Promotion Dialog — always prompts for your choice; underpromotions are fully supported

Requirements

An OpenRouter API key is needed for the AI coach and commentary. Chess playing (Stockfish) works without it.

More information

Download

Download
chess-buddy.zip 146 MB

Install instructions

Windows only for now.

Installation

  1. Download the zip and extract it to any folder
  2. Run chess buddy.exe

No further installation needed — Stockfish (the chess engine) is included.

Required: .NET 8 Runtime

Chess Buddy uses C# and requires the .NET 8 Runtime. If the game fails to start, download and install it from Microsoft: https://dotnet.microsoft.com/en-us/download/dotnet/8.0 → Choose .NET Runtime 8.x.x under "Run desktop apps" → Windows x64.

Optional: AI Coach

The AI coaching and commentary features require an OpenRouter API key. To enable them:

  1. Create a free account at openrouter.ai and generate an API key
  2. Open Chess Buddy, go to Preferences, and paste your key into the API Key field

Chess analysis (Stockfish) works without this — only the coaching and commentary features require it.