Author: Uri Blass
Date: 07:56:08 06/05/02
Go up one level in this thread
On June 04, 2002 at 13:12:40, J. Wesley Cleveland wrote: >On June 03, 2002 at 22:50:10, John Merlino wrote: > >>On June 03, 2002 at 22:39:35, John Merlino wrote: >> >>>On June 03, 2002 at 19:06:31, Dieter Buerssner wrote: >>> >>>>On June 02, 2002 at 22:32:25, Dana Turnmire wrote: >>>> >>>>>-- -- -- -- -- -- -- -- >>>>>-- -- -- -- -- -- -- -- >>>>>-- -- -- -- -- -- BK -- >>>>>-- -- BP -- BP -- -- -- >>>>>-- -- WP -- WP -- WK -- >>>>>-- -- -- WN -- -- -- -- >>>>>-- -- -- -- -- -- -- -- >>>>>BB -- -- -- -- -- -- -- >>>>> >>>>>Here is the test position found in "The Mammouth Book of Chess." >>>>> >>>>>1Nxc5? >>>>> >>>>>This obvious, materialistic move throws away the win. White's c-pawn cannot be >>>>>advanced to the queening square without the help of the king, but this allows >>>>>Black to counter by attacking the e-pawn. White should not take the c-pawn, but >>>>>instead make progress on the kingside by manoeuvring his knight. >>>> >>>>Can you please show a (sample) winning line. My program went also for Nxc5 for 4 >>>>hours (on rather slow hardware). I tried to understand the pos myself. All I >>>>came up with - I cannot find improvement for white after this move, and I think, >>>>it is draw. However, I have no better idea, that secures the win. >>>> >>>>Regards, >>>>Dieter >>> >>>We just happened to have that book laying around, and since I hadn't done ENOUGH >>>typing today, I figured I'd quote the entire passage from "The Mammoth Book of >>>Chess", pg. 386, under the section entitled "Computer Chess". >>> >>>------------ >>>From Pachman-Hromadka, Prague Ch, 1944 >>> >>> Nxc5? This obvious, materialistic move throws away the win! "White's c-pawn >>>cannot be advanced to the queening square without the help of the king, but this >>>allows Black to counter by attacking the e-pawn" - Pachman >>> Supposing it were instead Black to move, the following variation is >>>enlightening: >>>1...Bd4 2.Ne1 Bf2 3.Nf3 Kf6 (or 3...Bd4 4.Nh4+ Kf6 5.Nf5) 4.Kh5 Bg3 5.Nh4! Bf2 >>>6.Nf5 Bg1 7.Nh6 Bd4 8.Ng4+ Ke6 9.Ng6 >> >>The last move here should be 9.Kg6, of course.... Sorry about that.... >> >>> >>[D]8/8/4k1K1/2p1p3/2PbP1N1/8/8/8 w - - >>> >>> White will now play Nf6-h7-g5+, etc., and win easily. However, if there were >>>no black pawn on c5, then Black would have sufficient counterplay to hold the >>>draw, since his king could use the c5-square to attack White's pawns. >>> Thus, in our start position, White should not take the c-pawn, but instead >>>make progress on the kingside by manoeuvring his knight. >>>------------ >>> >>>So, the question is, is that correct? Anybody care to throw some serious CPU >>>cycles at it? >>> >>>jm > >I let crafty run overnight and got nothing. Did you tell it not to use null move pruning or does it automatically avoid null move pruning in KBPP vs KNPP when the pawns are blocked? I did not analyze the position but it is clear that if white can win it without capturing the pawn it is only by a lot of zunzwangs. Uri
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