Author: Uri Blass
Date: 02:07:28 06/12/01
Go up one level in this thread
On June 12, 2001 at 04:30:48, José Carlos wrote: >On June 11, 2001 at 11:19:55, Robert Hyatt wrote: > >>On June 11, 2001 at 03:05:27, Uri Blass wrote: >> >>>On June 11, 2001 at 01:31:14, Jouni Uski wrote: >>> >>>>[D]8/4k3/2K5/6p1/6B1/7P/8/8 w - - >>>> >>>>I tested this simple draw position with 3 engines: >>>>Fritz5 +4,53 no TBs >>>>Goliath +3,39 no TBs >>>>Crafty18.7 +5,01 with 4 piece TBs >>>> >>>>Hmm. Should this already be solved poblem? >>>> >>>>Jouni >>> >>>The position is not simple draw. >>>I have not the tablebases to find out if it is a draw or not a draw but white >>>may try to force black to play g4 by zunzwang and to win after hxg4. >>> >>>Uri >> >> >>I have looked at this position a bit closer. It is not so easy to statically >>evaluate this one as a draw. Crafty does this early on, but it is possible for >>white to eventually zug black into moving. The problem is that if black really >>gets zugged, the pawn move will lose. Without the black pawn, this is trivially >>drawn, but with it, black has problems staying in front of the pawn. I think >>it is likely that many programs could actually lose this without tablebases. >>But in any case, Crafty discovers that there are problems here that make it >>non-trivial to claim it is drawn: the black king can't get into the corner >>and stick because white will him in and zug him to push the pawn and lose. > > I don't see why the black king can't get to the corner. The only way I see >white can force black to move the pawn is something like this: > >[D]7k/8/4B1K1/6p1/8/7P/8/8 b - - 0 6 > > Here, after ...g4: > > hg4 is stalemate > Bg4 is a draw due to the h pawn and white bishop. > > Of course, this is difficult to statically evaluate. > > José C. It is easy for me to evaluate it as a draw. It seems to me that every position when the following conditions hold is a draw: 1)white has the wrong bishop 2)the black king is at distance 1 from the right corner 3)black has at most one pawn. If black has more than one pawn when one of the pawns is in the right file to be captured by the white pawn then it may be a win for the stronger side. Uri
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