Mistake

A mistake is a move that causes a substantial deterioration. It may lose a piece or pawn, spoil a plan, allow a strong threat, or turn an advantage into an equal or inferior position. The damage can be immediate or emerge several moves later; not every mistake simply leaves a piece attacked.

In analysis systems, “mistake” usually sits between an inaccuracy and a blunder. Platforms do not necessarily share the same thresholds. The category depends on the change in practical or evaluated chances and on the position's context, not on an official point value.

During game analysis, the useful question is not only “What should I have played?” but also “Why did I choose this?”. The cause may be failing to consider an important move, stopping calculation before an opponent reply, misjudging which side stood better, or using time poorly. Identifying the cause creates a correction that can transfer to future games.