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Subject: Re: Can white win? (no)

Author: martin fierz

Date: 04:31:08 01/18/04

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On January 18, 2004 at 06:42:50, Uri Blass wrote:

>On January 18, 2004 at 05:29:59, Kurt Utzinger wrote:
>
>>On January 18, 2004 at 04:44:59, martin fierz wrote:
>>
>>>On January 18, 2004 at 02:27:35, Kurt Utzinger wrote:
>>>
>>>>On January 18, 2004 at 01:25:52, Kurt Utzinger wrote:
>>>>
>>>>>[D]8/8/5pk1/5b2/7K/3R3p/7P/8 w - - 0 1
>>>>
>>>>How on earth should White win this position? I see no way
>>>>to do this. Some reasons for my assumption:
>>>>
>>>>1.)
>>>>If White at some time takes the h3-pawn with the rook,
>>>>the pawn ending is a draw.
>>>>
>>>>2)
>>>>The only try would be to win Black's f6-pawn. But
>>>>this can't be done.
>>>>
>>>>3)
>>>>But even in the case that due to some Zugzwang
>>>>White wins the f6-pawn, the position still looks
>>>>drawn.
>>>>
>>>>Any counter arguments.
>>>>Kurt
>>>
>>>hi kurt, uri,
>>>
>>>this is an interesting position. the first thing to note are a couple of
>>>theroetically known endgames:
>>>
>>>-> if white succeeds in winning both black pawns, he wins
>>[D]7k/R7/7P/6K1/8/3b4/8/8 w - - 0 1
>>>
>>>-> however, if he is careless then, he only draws
>>>[D]7k/R7/7P/6K1/8/3b4/8/8  w - - 0 1
>>>
>>>these two endings are just interesting so i posted them anyway. but they are
>>>irrelevant. the relevant ending is if white wins the f-pawn:
>>>
>>[D]8/8/6k1/5b2/7K/3R3p/7P/8 w - - 0 1
>>>this is supposed to be a win in endgame theory AFAIK, and that is the
>>>counter-argument to kurt's argument #3 - if white succeeds in winning f6, he
>>>will in fact win the game. in addition, the wins of this type of endgame usually
>>>are very very deep, so even searching this position to 30 or 40 ply might not be
>>>enough to see the win of the h-pawn.
>>>
>>>if somebody has the KRPKBP tablebase and time to spend he could run the original
>>>position over night and se what happens...
>>>
>>>cheers
>>>  martin
>>
>>    Hi Martin
>>    Indeed a very interesting position in which the main
>>    question remains: can White succeed in winning Black's
>>    f6-pawn?
>>    Kurt
>
>It seems that white can do it(or to win the h3 pawn)
>Otherwise I see no explanation for Yace increase in the score.
>
>Uri

uri, wouldn't you be seeing a huge jump in the score if it really saw the win of
a pawn? but you only see +0.02 or so on next iterations. i let shredder 8
(unfortunately without TBs) run overnight on the starting position, it reached
depth 38, and the score on d30 was +1.50 and at d38 +1.52 (or something like
that). i would guess that it sees it can get a tiny bit better piece placement
which explains +.02 difference, but nothing more. i added the 4-man TBs now, and
am trying a shootout at 1min/move, and will repeat the deep search later - but i
really don't think your interpretation of yace's score is right here - why
shouldn't it evaluate this position as +1.xx? it's clear that only white has
winning chances...
i also would guess that this position is a draw - but who knows?

cheers
  martin



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