Free chess analysis board with Stockfish

Three ways to load a position

Drag the pieces from the starting position, paste a FEN to jump straight to a specific position, or paste a full PGN to pick up where a game finished. Copy FEN hands the current position back so you can save it or share it somewhere else.

Every move you play from there becomes your own variation. Back steps out of it one move at a time, and Reset returns the board to the starting position. The engine starts on your first move — or on Start engine, if you would rather have it running before you touch anything — and from then on it watches every position on the board.

Reading the evaluation honestly

The bar and the number are centipawns from White’s point of view. Positive favors White, negative favors Black, and a mate score takes over when a forced mate is on the board. What the number does not tell you is how hard the position is for a human to play, and that gap is where most club-level games are actually decided.

The depth readout is there for the same reason. Engine evaluations are provisional until the search settles; a tool that shows you a confident number without telling you how far it looked is hiding the one thing you need to judge it. Watch a tactical position climb through the depths and you will see the number move a long way.

Analyzing a position rather than collecting evaluations

The most common way to waste time with an analysis board is to click through a game watching numbers go by. Nothing sticks, because you never committed to anything the engine could correct.

A better loop takes about a minute per position. Decide what you would play and why. Play it on the board. If the evaluation holds, you were right for a reason you can now name. If it drops, step back and find the move you missed — and try to state what you failed to look at, not just which move was better. That sentence is the part that transfers to your next game.

When the board explains a move — and when it says nothing

Where a named principle genuinely applies, the panel names it: material hanging, a threat that needs meeting, a square worth occupying. That text comes from a deterministic rule engine reading the board directly, not from a language model producing plausible chess prose, and the engine keeps a veto over anything the rules want to say.

Most of the time it stays silent. On our own measurement corpus the principle layer declines to speak in roughly seven positions out of ten, because most positions are not about a principle — they are about a concrete line. We would rather show you nothing than dress up an engine move in a rule that was not really doing the work.