What is a brilliant move in chess?

A brilliant move gives material away and is the only move in the position that keeps what you had. Both halves matter. The sacrifice is what makes it look wrong to a human; being the only move that works is what makes it right.

That is why brilliancies are rare. Most sacrifices are not brilliant — they win the material straight back, or they were simply bad — and most only-moves are not brilliant either, because finding the one quiet move that holds a position is a different skill and gets its own grade.

Here is the actual rule this analyser applies. Four things have to be true at once:

1. 1The engine agrees. The move has to be the engine's own first choice. A sacrifice that is second best is not brilliant however pretty it looks — it is a move that cost something.
2. 2Nothing else would have done. It has to be the only move that holds the position. If two moves keep the advantage, neither was a discovery. Taking back on the square you were just captured on is excluded even when it is forced: a recapture is not something you found.
3. 3Material really is given up. Every capture on the destination square is played out, cheapest attacker first, to see who comes out ahead — a static exchange evaluation. The move counts as a sacrifice only if it loses at least a pawn's worth by that reckoning. A queen that lands somewhere it can safely be taken back on is not a sacrifice.
4. 4You were not already lost. The position after the move has to leave you with a real game — at least a 45% chance by the engine's reckoning. A spectacular sacrifice in a position that was already lost is a swindle attempt, and it deserves a different word.

The grade next to it is the one most brilliancies turn out to be. Both require the same thing — the only move, found — and they differ on one point: whether you had to give anything up for it.

Chess.com shows the same word and does not publish the rule behind it. Nobody outside can say exactly what it tests, and this site does not pretend to know — so rather than approximating somebody else's label, it applies a rule that can be stated in full, as above, and applies it strictly.

The practical effect is that a brilliant move here means something specific. If you get one, the engine is telling you that you found a move that gave material away, that no other move would have held the position, and that you were not lost when you played it.

Every move you have played is graded by the same rule, and Stockfish runs in your own browser — nothing is uploaded and no account is needed. Paste a game or import from chess.com, read how the other ten grades work, or see what an accuracy score actually means.