WhyBlunder

WhyBlunder is a powerful chess game analyzer that runs entirely in your browser using WebAssembly. It uses the Stockfish engine (compiled to WASM) to provide detailed analysis of chess games — no server or installation required.

Features

• Analyze chess games from PGN notation
• Identify blunders, mistakes, and inaccuracies
• Suggest better moves with detailed explanations
• Interactive web UI to visualize the analysis
• Runs 100% in-browser — no backend, no installation

Usage

Simply open the app in your browser:

👉 whyblunder.vercel.app

1. Paste a PGN (Portable Game Notation) of a chess game into the text area
2. Click Analyze Game
3. Once analysis is complete, you can:
   • View the game move by move using the navigation buttons
   • See analysis for each move, with mistakes and blunders highlighted
   • Click on any move in the analysis panel to jump to that position

Running Locally

The frontend is a static site — just serve the repo root with any static file server:

# Using Python's built-in server
python3 -m http.server 3030
# Then open http://localhost:3030

Or use any other static server (e.g. npx serve .).

Deployment

The app is deployed as a static site on Vercel.

Acknowledgements

• Stockfish — The powerful chess engine (compiled to WebAssembly)
• chessboard.js — JavaScript chessboard component
• chess.js — JavaScript chess library