I was doing a puzzle and this game came up:
In move 31 and 42 Stockfish gives a draw, though I can't find a perpetual or a repetition. If one follows the suggested line by Stockfish the draw is gone. What's happening here?
Well it is not draw, it is evaluation 0 i.e. even. It looks strange indeed. I suspect some bug.
@tpr ok, let's say drawish...at least the evaluation says that, though white is a whole piece down and the position doesn't offer too much compensation.
Equal and draw are not the same.
I do agree with you that there is some anomaly in the evaluations at moves 31 and 42 and I suspect it is a software bug.
You could try copying the pgn and re doing the evaluation.
Stockfish scores twofold repeats as 0
@brudi so it seems indeed...I've never realized that. Not sure if this is really helpful in an analysis unless one really has the opportunity to claim the draw.
So mystery solved thanks to brudi. It's a great thing to keep in mind to prevent further confusion in the future.
zetaofsix that'd be a good question for debate, whether it's helpful or not. There is definitely a positive and negative to it.
Evaluation at zero for a repetition is done that way so the engine does not waste time analyzing the same position again. It prevents the variations tree from growing unnecessarily
#1, if you let Stockfish thinking for a couple of seconds on these 2 positions, it returns a score = 0. That means it found nothing special.
But if you let it searching longer, it found an advantage for black.
The deeper you let it search, the better is the evaluation.
