Author: Ricardo Gibert
Date: 07:52:06 06/15/00
Go up one level in this thread
On June 15, 2000 at 03:26:14, Bruce Moreland wrote: >On June 14, 2000 at 00:07:46, Ricardo Gibert wrote: > >>On June 13, 2000 at 23:33:05, Christophe Theron wrote: >> >>>>[D]8/8/8/8/P1k1P3/6p1/7p/7K w - - 0 1 >>>> >>>>Here is another example that I invented when the rule fails. >>>> >>>>The rule is correct here that white pawns are unstoppable but cannot see that >>>>black pawns+king also cannot be stopped. >>>> >>>>Uri >>> >>> >>>What happens here? Isn't white winning? >>> >>>I shoud seriously try to learn how to play chess. :) >>> >>> >>> Christophe >> >>Kc4-d3-e3-f2 folowed by g2 wins. If white tries to stop this with Kg2, then h1=Q >>Kxh1 Kf2 anyways. The white pawns are essentially irrelevant, since they are too >>slow. > >If the e4 pawn is on f4, white wins. If white advances the e4 pawn, the pawn >queens in a bad spot and can't do anything in time to prevent black from mating. > If white advances the a-pawn, the e-pawn blocks the new queen. With the e-pawn >on f4, the a-pawn is fast enough. > >bruce Your choice of moving the pawn to f4 is unfortunate. White can _also_ win in a different way, unrelated to the fact that the diagonal is blocked e.g. [D]8/8/8/8/P1k2P2/6p1/7p/7K w White can _also_ win with 1. f5 since he has the possibility of queening the f pawn with check. To make the point you intended, you need to move the pawn all the way over to h4: [D]8/8/8/8/P1k4P/6p1/7p/7K w Winning with the theme you noted. The a-, b-, f- & g-pawns comprise special cases, since upon Queening they "instantly" interfere with Blacks operations on the K-side. With the a-pawn: A Queen on a8 will control g2. (your case) With the b-pawn: A Queen on b8 will control g3, the square Black needs to deliver mate! In general, good for a draw. With the f-pawn: A Queen on f8 will check the White King on the f-file. With the g-pawn: A Queen on g8 will control g2. An exception in the above cases is when the Queen gets blocked as you noted. Cases with a b-pawn have some special interest: [D]8/8/8/8/1P2P3/6p1/7p/2k4K w 1.b5 Kd2 2.b6 Ke3 3.b7 Kf2 4.b8=Q g2+ 5.Kxh2 g1Q+ 6.Kh3= And to show just how tricky it is to make rules to cover all the cases: [D]8/8/8/8/1P5P/6p1/7p/2k4K w 1.b5 Kd2 2.b6 Ke3 3.b7 Kf2 4.b8=Q g2+ 5.Kxh2 g1Q+ 6.Kh3 Qg2# I'm sure we have not exhausted all the possibilties.
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