Chee - Live Chess Analysis

About

Chee adds a real-time analysis panel to your chess games on Chess.com and Lichess.org.

It runs Stockfish (one of the strongest chess engines) entirely in your browser using WebAssembly — no server, no account, no data sent anywhere.

Analysis:
• Multi-line analysis — see the top 3–5 best moves and continuations
• Adjustable search depth (15–22 ply) with optional wait-for-full-depth
• Move classifications — Brilliant, Crazy, Best, Excellent, Good, Inaccuracy, Mistake, Blunder
• Move guard — pick up a piece to see which destination squares are bad moves (! badges)
• Tactical insights — dashed arrows show the best move after Mistakes and Blunders
• Pre-move hints — see the engine's best move or classification-based hint arrows
• Trap detection (Trapboy) — finds traps via sacrifice detection, tempting capture analysis, and a 10-trap opening database (Legal, Lasker, Noah's Ark, and more)
• Crazy sacrifice detection — flags wild material sacrifices that maintain advantage
• Book move detection with continuation arrows from ECO opening database

Display:
• Board preview — hover analysis line moves to see the predicted position on the board
• Eval bar showing who's winning at a glance
• Eval score chart — SVG area chart with hover tooltip tracking the game
• Opening name display — 193-entry ECO opening database
• Accuracy tracker — running accuracy percentage (chess.com-style formula)
• Arrow overlays on the board for suggested moves

Export & Debug:
• PGN export — copy annotated PGN with eval comments, NAG codes, and player names
• Copy FEN to clipboard with one click
• Copy debug info — one-click diagnostic dump for troubleshooting

UI:
• Compact 2-column settings popup with section headers
• Draggable panel — drag the header to reposition, double-click to reset
• Resizable panel — drag the bottom-right grip to adjust width
• Minimize or hide the panel (Alt+C keyboard shortcut)
• Catppuccin theme system — Latte, Frappé, Macchiato, Mocha, or auto-match the site theme
• All settings apply in real-time — no page reload needed

Supported sites:
• chess.com — live games (/game/*, /play/*)
• chess.com — puzzles, rush, battle, learning (best move arrow, each togglable)
• chess.com — daily chess (best move arrow, live-togglable)
• lichess.org — all game pages
• lichess.org — training, storm, racer, streak (best move arrow, each togglable)

All analysis runs locally in your browser. No data is collected or transmitted.