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Subject: Re: fantastical kingside attack with ...h5

Author: Robert Hyatt

Date: 13:08:59 09/06/01

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On September 06, 2001 at 15:14:43, Uri Blass wrote:

>
>I did not say that programs can see the repetition but that they can
>see Kh1 for good reasons.
>

There we will just have to disagree.  The only "good reason" to play Kh1
is something _concrete_.  IE "I played that because I saw that if I played
Kf1 I would walk into a perpetual."  Or "I played Kh1 because I saw that if
I played Kf1 I would lose a pawn."  Or something reasonable.  Just choosing
Kh1 makes little sense.  The king should centralize unless there is some
compelling reason why it should not.  And Kh1 is not centralizing anything
at all.  H1 is one of the worst 4 squares on the board for a king to
occupy, _unless_ there is a compelling reason for it to sit there.

If DF can't see a compelling reason, it is just choosing it for random
(and wrong) reasons...

I have had my program choose the right move for the wrong reason, on many
occasions.  I try to fix those as I consider them "bugs" and not "good
luck things."



>
>The reason that Kh1 does not give black the chance of Qe3
>is good enough.
>
>Humans are also going to choose Kh1 even without seeing the
>draw by Qe3 if they understand that after Kf1 Qe3 black has chances
>when after Kh1 black has no chances and has to go to a losing endgame.
>

Kh1 or Kf1 doesn't actually prevent Qe3.  It just means that if the king is
on f1, there is a possible perpetual, while if the king is on h1 there is not.
But the queen can go there either way.  Which is why I discount any program
playing either move unless they see _the_ reason for the move.





>It is about king safety's evaluation
>The micros can see that the white king is not safe after Kf1
>and black has chances by Qe3 when deeper blue could not see it.

I don't believe that for a minute, otherwise DF would not keep getting
tricked by king safety issues against Nemeth.  If it could understand that
Kf1 is worse than Kh1 based on evaluation, Nemeth would not keep mating the
program with straightforward attacks.


>
>It is possible that deeper blue saw that both kings are not safe and
>simply added king safety scores.


That is possible.  Or it saw that both _are_ safe since no program can
see the resulting perpetual after Kf1.  And given that both appear to be
equally safe if you can't see the draw, then Kf1 is more logical.



>
>If it did it then it is clearly wrong to do it because if both kings
>are not safe you cannot be sure about the result and the evaluation
>should be closer to a draw.
>
>Uri

That sounds like Gandalf.  It doesn't work.




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