How to Read Chess Heatmaps

An eval bar tells you who is better. A chess heatmap shows why. Chessyi paints square control, attacks, defense, mobility, tension, and king safety as live colour overlays on the same board where Stockfish runs.

This guide explains how to read each layer so you stop guessing from numbers and start seeing structure, tactics, and plans.

Start with square control

Control overlays show who influences each square: your colour, theirs, or contested territory. Look first at the centre (d4, d5, e4, e5) and the squares around both kings.

If the opponent owns more central squares, your pieces often feel cramped even when material is equal. That is the kind of story an eval number alone rarely tells.

Blue-leaning control usually favours White influence; purple-leaning favours Black (exact colours depend on the overlay).
Orange or mixed zones mark contested squares — typical break points and tactical flashpoints.
Compare control before and after a candidate move to see what the move actually fights for.

Use attacks, defense, and danger together

Attack overlays highlight pressure. Defense overlays show support. Danger blends piece value with how under-defended a unit is.

When a queen or rook lights up as dangerous while the king is soft nearby, you are looking at a real tactical motif — not just a temporary Stockfish swing.

Read mobility and tension in closed positions

Mobility heatmaps colour pieces by how many useful moves they have. Rim knights and blocked bishops look dull; open-file rooks and long diagonals look bright.

Tension overlays mark contested contact points — pawns that can capture, pieces facing each other. Rising tension often precedes forced sequences worth calculating deeply with Stockfish.

A practical study loop

Import a PGN or load a master game. Toggle control and king safety first. Then switch on Stockfish multi-PV and ask: does the engine move improve the map you already see?

That loop — visualize, then verify — is how Chessyi is meant to be used. Heatmaps do not replace the engine; they make engine lines memorable.

FAQ

Do chess heatmaps replace Stockfish?

No. Heatmaps explain structure and pressure visually. Stockfish still finds concrete tactics and best moves. Chessyi runs both on one board.

Which heatmap should beginners start with?

Start with Attacks and Square control. They map directly to “what is hanging?” and “who owns the centre?” before you add tension or mobility layers.

Turn coloured squares into concrete plans