Chess game review: accuracy, mistakes and critical moments
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- Book
- Best move
- Brilliant
- Inaccuracy
- Mistake
- Blunder
A game report turns a list of moves into answers: where you played well, where the game turned, and what you could have done instead. ChessWOW builds a report for every game you import, play or set up, using Stockfish 19 on your device. This page explains each part of the report, so the numbers mean something when you look at your next game.
Accuracy: what the percentage measures
Accuracy describes how close your moves came to the engine's choices, on a scale from 0 to 100. A move gets full marks when it keeps all of your winning chances; it loses points for every percentage point of winning chances it gives away. The game accuracy combines all of your moves into one number. ChessWOW uses the method Lichess has published for this, based on winning chances rather than raw pawn values.
Why winning chances? Because a pawn is worth very different amounts in different positions. Giving up a pawn in an equal position is serious. Giving up a pawn when you are a queen ahead changes almost nothing. Measuring the loss in winning chances treats both cases fairly.
Three things to keep in mind:
- Accuracy depends on the game. A quiet game with few difficult decisions produces higher numbers than a sharp tactical fight, even for the same player.
- Different sites, different numbers. Chess.com calculates accuracy with its own method. A game can show different values on different sites, and neither is wrong.
- Short games say little. With only a few moves, one error dominates the result. The report tells you when a game is too short for general conclusions.
Inaccuracy, mistake, blunder
Every move is classified by how much winning chance it gives away. In ChessWOW, a move counts as an inaccuracy from 5 percentage points, a mistake from 10 and a blunder from 15. Moves that keep the position at engine level count as best, and moves from established opening theory count as book. A brilliant move is rare: a sacrifice that is also the only good move in the position.
The classification tells you where to look, not how bad you played. Three inaccuracies in a row in a slow position may cost more over time than one blunder your opponent did not notice.
Evaluation loss per move
Next to accuracy, the report shows the average evaluation loss per move in pawns. It compares each of your moves with the best move Stockfish found. Lower is better; 1.00 means you gave away the equivalent of one pawn per move on average. This is the classic measure many players know as average centipawn loss, expressed in pawns.
The evaluation graph
The graph shows the evaluation after every move, from your point of view. Above the middle line you were better, below it your opponent was. Read it like a map of the game:
- Steep drops are the moments you lost ground, usually the critical moments below.
- A slow slide over many moves often points to a strategic problem: a bad piece, a weak pawn, a plan that did not work.
- Crossing the middle line shows where the game changed hands.
Critical moments in plain words
The most useful part of the report is the list of critical moments: the positions where the evaluation swung clearly. For each one, ChessWOW shows the move that was played, the better alternative and a short explanation in words of what changed. You can open any critical moment on the analysis board and play through the lines.
Then practise them. With "Retry" you see the position again and play the move yourself. If it is the right one, the board turns green; if not, an arrow shows the better move. Coming back to the same positions a few days later is one of the simplest ways to stop repeating a mistake.
Nf6?? Qxf7#
Which opening did you play?
The analysis shows the name of the opening, taken from an openly licensed opening database. The report counts how many of your moves were still opening theory. If you leave theory early in every game with the same opening, that is a clear hint where to study next.
Quick check or full report
A quick check runs at low depth and takes at most 25 seconds. It is useful for a first look right after a game. The full report calculates more thoroughly and is the better basis for the conclusions above. You choose the thoroughness in the settings. ChessWOW is free to download; unlimited reports are part of ChessWOW Pro, which you can try with a free daily allowance or a free trial depending on the current offer.
Questions and answers
Why is my accuracy different from Chess.com?
Chess.com uses its own calculation. ChessWOW follows the published Lichess method, which measures the loss of winning chances. Both are valid; compare games within one system.
What is a good accuracy?
It depends on the game and the time control. Compare your accuracy across similar games rather than with a fixed target.
What is the difference between a mistake and a blunder?
Both lose winning chances. In ChessWOW a mistake costs at least 10 percentage points and a blunder at least 15.
What makes a move brilliant?
A sacrifice that is also the only good move in the position. It is rare by design.
How long does a report take?
A quick check takes at most 25 seconds. A full report takes longer and depends on the length of the game and your device.
Does the report work offline?
Yes. The report runs with Stockfish 19 on your device.
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