3

The FEN is:

r2qk1r1/ppp2p1p/2n1bn1Q/4p1B1/8/2P4P/PP1NpKP1/R5NR b kq - 0 1

engine

Clearly black is winning because the white bishop can be captured (with a discovery available if white recaptures). However, the stockfish eval seems strange - why would it suggest that playing an intermediate Rg6 is better? The continuation is Qh4 Rxg5 Qxg5 anyway, which is just a slower way to do the same thing. Wouldn't it be better to play the most direct move Rxg5?

Then I am also confused about the 3rd recommendation of e1=B+, why would it suggest to underpromote there?

1
  • -8.8 and -8.9 are basically the same evaluation
    – David
    Nov 26, 2022 at 11:41

2 Answers 2

3

I think that in the case of the immediate ...Rxg5, Stockfish has seen one move deeper than in the version with ...Rg6 first. As a result the evaluation is slightly different - 0.1 less, in this case. So it ranks ...Rg6 first. It doesn't really matter either way, it's just an artifact of how engines work.

Same for ...e1=B+. It gets captured immediately, so it's effectively the same move as ...e1=Q+ that would also be captured immediately. Which one it happens to show is essentially random, it doesn't have a builtin preference for promoting to a queen in cases where it doesn't matter at all.

7

No particular reason. Note the scores, -8.9 and -8.8, practically indistinguishable. Stockfish simply saw the same sequence of tactical response with and without the move ...Rg6. The line ...Rg6 came first due to random fluctuation.

1
  • 1
    FWIW, a human player might play the slower version to have a little more time on their clock.
    – Philip Roe
    Nov 3, 2022 at 20:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.