Training notebook · Review your games
Centipawns, winning chances and accuracy: read chess scores carefully
An engine score is not a literal pawn count or a universal win prediction. Learn which comparisons help you understand a chess decision.
A score summarises an evaluated position
A chess engine’s numerical score expresses its assessment under its evaluation and search system. Positive and negative values normally distinguish the favoured side, but check the interface’s perspective before reading the sign. Some displays follow White; others may orient information differently.
A centipawn is conventionally a hundredth of a pawn unit, yet a displayed advantage is not a receipt for material you can immediately collect. King safety, activity, structure and concrete tactics all contribute. A side can be materially ahead while the engine prefers the opponent’s attack.
Winning chances add a model
Some chess services transform engine scores into a winning-chance scale intended to be more understandable for humans. That transformation depends on a model and its reference data. It is not a personalised prediction for your next game, your exact time control or every possible opponent.
Lichess explains that its accuracy metric uses changes in modelled winning chances rather than treating equal centipawn losses as equally significant in every position. This helps explain why a numerical drop in an already overwhelming position can mean something different from the same drop in an equal one. Other services need not use the same formula.
Accuracy is not your rating
An accuracy percentage describes moves under a particular analysis method. It does not measure all the skills involved in competitive chess and does not provide a direct rating conversion. An easy position with many safe moves is different from a difficult defence requiring repeated precise choices.
Avoid comparing percentages from different services as if they were marks on the same exam. Engines, search settings and classification formulas can differ. A high score in one short game also cannot establish that a player cheated. Report genuine concerns through the playing platform rather than drawing a conclusion from one percentage.
Read the move behind the number
When a score changes sharply, inspect the position before and after the move. Ask which defence or tactical resource appeared or disappeared. Follow the line until you can explain the practical consequence. The useful lesson might be an exposed back rank, an unfavourable trade or a king trapped without escape squares.
For a study exercise, compare two candidate moves and write a verbal assessment before revealing their scores. Then investigate the first concrete disagreement. This keeps the number connected to chess reasoning. If a small difference remains mysterious, do not invent a strategic story just to match it. Mark it unresolved and prioritise errors whose causes you can identify. Numbers are valuable evidence, but the board and the continuation show what you should practise next.
Put the practice into a routine
Where Brass Pawn fits
Brass Pawn offers engine feedback and move grading in practice. Do not assume its displayed labels or percentages use the same thresholds as another service, or that a training score predicts a competitive rating.