Chess Pressure

A web application that visualizes pressure maps on a chess board -- showing which squares are controlled by white vs. black across every move of a game.

What is "pressure"?

For each square on the board, pressure is the net number of pieces attacking it. Positive values mean white controls the square; negative means black does. Two modes are available:

• Unweighted -- each attacking piece contributes +1 or -1.
• Weighted -- each attacking piece contributes its material value (pawn=1, knight/bishop=3, rook=5, queen=9, king=1).

Features

• Step through famous built-in games move by move and watch the pressure heatmap evolve.
• Upload your own PGN to analyze any game.
• Make moves from any position and see legal moves + pressure updates in real time.
• FastAPI backend with a lightweight static frontend.

Built-in Games

Game	Year	White	Black
The Immortal Game	1851	Anderssen	Kieseritzky
The Opera Game	1858	Morphy	Duke of Brunswick & Count Isouard
Kasparov's Immortal	1999	Kasparov	Topalov
Fischer vs Spassky, Game 6	1972	Fischer	Spassky
Kasparov vs Deep Blue, Game 2	1997	Deep Blue	Kasparov

Quickstart

# Install dependencies
pip install fastapi uvicorn python-chess

# Run the server
python -m chess_pressure.app

The app starts on http://localhost:8888.

API

Method	Endpoint	Description
GET	/api/games	List built-in games
GET	/api/games/{id}	Load a built-in game (headers, moves, pressure frames)
POST	/api/parse	Parse a PGN string ({"pgn": "..."})
GET	/api/legal?fen=...	Get legal moves for a FEN position
POST	/api/move	Make a move ({"fen": "...", "uci": "e2e4"})

Project Structure

chess_pressure/
  __init__.py
  app.py       # FastAPI routes and static file serving
  engine.py    # Pressure computation, PGN parsing, move logic
  games.py     # Built-in famous games (PGN data)

License

MIT