Stockfish misevaluations:

Henk · Post by **Henk** » Mon Apr 22, 2019 3:11 pm

I encountered this position in a real human-human game. Me playing with white.

Stockfish 10 evaluates this as +3.30

[d] 4b3/5k2/p5p1/P2p1p1p/1PpPrP1P/2P2QP1/5K2/8 w - - 6 8

Stupid engines

hgm · Post by **hgm** » Mon Apr 22, 2019 4:37 pm

Well, what can you expect from an engine that is only good on average?

mar · Post by **mar** » Mon Apr 22, 2019 5:06 pm

And what's wrong with that? White will eventually sac a pawn, break free and win the game

It will take some time with 50 move rule, sure, but white will win.

hgm · Post by **hgm** » Mon Apr 22, 2019 5:15 pm

With the Bishop on b5 the only Pawn you can sac is the g-Pawn, and after fxg4 black will simply put his King on f5, and white has nothing. Actually I would not be surprised if it was lost for white after such a sac.

Henk · Post by **Henk** » Mon Apr 22, 2019 5:20 pm

mar wrote: ↑Mon Apr 22, 2019 5:06 pm And what's wrong with that? White will eventually sac a pawn, break free and win the game
It will take some time with 50 move rule, sure, but white will win.

How? I don't see it. Black can block everything. You mean sacrifice the b pawn. But then Bb5, Rc6 and Ke8 and Queen can't pass.

By the way Komodo 9: +1.82

Henk · Post by **Henk** » Mon Apr 22, 2019 5:24 pm

hgm wrote: ↑Mon Apr 22, 2019 4:37 pm Well, what can you expect from an engine that is only good on average?

Maybe best is to evaluate a position by playing some games and taking the average score. I don't know. Looks like alpha beta fails.
Zero method would do better.

mar · Post by **mar** » Mon Apr 22, 2019 5:43 pm

hgm wrote: ↑Mon Apr 22, 2019 5:15 pm With the Bishop on b5 the only Pawn you can sac is the g-Pawn, and after fxg4 black will simply put his King on f5, and white has nothing. Actually I would not be surprised if it was lost for white after such a sac.

Yes, maybe I was too optimistic and this is indeed a draw with perfect play.
Is there actually any (non-buggy) engine to score this fortress as a dead draw?
This doesn't seem like a typical pawn fortress due to the open e file.
I just tried Critter which I know had some fortress detection code and it still scores this as +2.6 for white.

mar · Post by **mar** » Mon Apr 22, 2019 5:46 pm

Henk wrote: ↑Mon Apr 22, 2019 5:24 pm Maybe best is to evaluate a position by playing some games and taking the average score. I don't know. Looks like alpha beta fails.
Zero method would do better.

Maybe a random mover would score this position properly as 0.0

Raphexon · Post by **Raphexon** » Mon Apr 22, 2019 6:31 pm

Latest dev version of SF thinks it's winning.

+5.7 at depth 53/60
Still +5.38 at 62/73
Still +5.38 at 70.

I'll let it run for a few hours, maybe it will reach 127...

PK · Post by PK » Mon Apr 22, 2019 7:20 pm

Perhaps it is a draw, perhaps a win, but it is white to move. Does any engine try immediate b5?

Stockfish misevaluations:

Stockfish misevaluations:

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