A Field Guide to the Position

Rate every move.
Not just one.

Click any piece on Chess.com or Lichess and see every legal move it can make, ranked and color-coded by Stockfish, built to help you understand chess, not just play it.

Add to Chrome · Free See pricing

Also works in Microsoft Edge. Edge can install extensions directly from the Chrome Web Store.

Field Notes

Everything the engine shows you

Most tools hand you a single "best move" and leave the rest unexplained. StockFishy annotates the whole position, piece by piece.

Every legal move, rated

Click any piece to reveal all of its legal moves at once, each ranked and color-coded on a six-step scale from Best down to Blunder, the same vocabulary used on Chess.com and Lichess.

II.

A board-wide overview

Before you click anything, every piece that can move is marked with a quiet ring and its own rating badge, and the three strongest moves on the whole board are drawn as arrows.

III.

A preview of the reply

A dashed arrow shows the response Stockfish expects from your opponent after the top move, a small look ahead, not just a single ply.

IV.

Continuous analysis

Toggle it on and the position re-analyzes itself after every move, yours and your opponent's, with nothing left to click.

Runs on your machine

Stockfish is compiled to WebAssembly and runs entirely inside your browser: Stockfish 18 by default for instant analysis, or flip on Deep Analysis for the full-strength Stockfish 19 engine. Either way, no position, no move, no game is ever sent to a server.

VI.

A keyboard shortcut

Alt+A (Option+A on a Mac) triggers analysis without reaching for the mouse, useful mid-game on either site.

The Rating Scale

Six shades of judgment

Every move is classified relative to the position's best option, so a glance at the color tells you as much as the number.

Best Excellent Good Inaccuracy Mistake Blunder

Each move also shows a raw score. A plus number favors whoever's about to move, measured in pawns, so +1.2 is a modest edge and +4.0 is close to winning. A minus number favors the opponent instead. M3 means a forced mate in three moves; M-3 means walking into mate in three if the opponent finds the best defense.

The Engine

Real Stockfish, not a clone

StockFishy runs the actual official Stockfish engine, compiled to WebAssembly. No proprietary model, no watered-down "chess AI", the same open-source engine top players and other analysis tools rely on.

Stockfish 18

Default

Released January 31, 2026

NNUE evaluation: a neural network trained on billions of positions estimates who's better, rather than counting material with hand-written rules.
Roughly 46 Elo stronger than Stockfish 17 in engine-vs-engine testing.
A lightweight build, so analysis loads and runs instantly in your browser.

Stockfish 19

Deep Analysis

Released September 5, 2026

New SFNNv16 network architecture: drops redundant threat features and adds pawn-structure features the previous network didn't track.
Retires the smaller secondary network Stockfish used since version 16.1, folding evaluation into one unified network for steadier judgment in sharp, complex positions.
Trained with quantization-aware training across hundreds of billions of positions.

Rate every move.Not just one.