The moment your game ends, the labels appear: brilliant, best, excellent, good, inaccuracy, mistake, blunder. They look like a report card, and like any report card, they can mislead you if you do not know how they are graded.

What each label is based on

Every move you play is compared against what the engine considers the best move in that position. The classification depends on how much worse your move is compared to that best move, measured in evaluation:

• Best: the engine's top choice (or within a hair of it).
• Excellent / Good: solid, close to the best move, no harm done.
• Inaccuracy: a real dip in evaluation, but not enough to change who is winning.
• Mistake: a serious error that shifts the evaluation significantly — often turning a winning position into a drawable one.
• Blunder: a move that costs the game — losing material or going from a playable position to a lost one.

Brilliant is a special case

"Brilliant" is a marketing label as much as an engine verdict. It tends to appear when you sacrifice material for a powerful, hard-to-find follow-up. It is exciting, and it is correct, but it is also rarer than people think and not always more useful than a quiet "best" move.

If you play a quiet, unglamorous move that keeps a +2 position, you will get "excellent". If you play a flashy sacrifice that also keeps +2, you might get "brilliant". The board position was equally good either way — the engine is just rewarding the difficulty of finding the sacrifice. Do not chase brilliance. Chase best moves.

Why a "mistake" can feel unfair

The classification depends on the position you were in, not just the move. Play a slightly imprecise move in a totally winning position and the engine will call it a mistake, because the evaluation dropped from +5 to +3. In a human sense nothing was wrong with your game — you are still winning. The engine just has no concept of "good enough."

This cuts the other way too: an accurate move in a losing position might be labeled "best" even though the position is hopeless. Labels describe the move relative to the position, not whether you won or lost.

How to actually use the labels

Do not grade yourself on how many brilliant moves you made. That is decoration. The useful information is the pattern of your errors. If most of your mistakes happen when your opponent has the initiative, you need to work on defense and counterplay. If they happen in quiet positions, you need to work on planning.

The move classification table in the Replay tab is built exactly for this: it lists every classified move in the game. Skim it for the blunders and mistakes, understand each one, and ignore the rest. That handful of moves is your actual lesson.