Author: Howard Exner
Date: 08:50:41 09/08/00
Go up one level in this thread
On September 08, 2000 at 11:20:01, Howard Exner wrote: >On September 08, 2000 at 09:46:36, Stephen A. Boak wrote: > >>On September 08, 2000 at 01:05:22, Howard Exner wrote: >> >>>A nice win by Gelfand. >>>[D]3k4/2pP2b1/3p2P1/1K1P1BP1/8/8/8/8 w - - >>> >>> >>> id Gelfand,B - Ye Jiangchuan; bm Kc6; >>> >>>In the game Gelfand played Kc6 and Ye Jiangchuan resigned. >>>The winning technique as explained on Kasparov's site explains >>>that white's bishop must go to either a4 or e8, allowing the white king to >>>penetrate via the f5 square. Both work nicely, yet it made me wonder if computer >>>programs will discover this winning technique. How do programs >>>fair here? The theme of first protecting the d7 pawn with the king, then >>>with the bishop(on a4 or e8), and finally marching the king around to the >>>kingside may prove difficult for programs. >> >>Somebody me help me analyze a clear win here. I sure can't find it, even with >>Fritz6's help. >> >>I tried the case of Be8 (suggested by Shipov as winning). >> >>I tried Fritz6a and it couldn't find the win, even after I played out many of >>the moves in the supposed winning strategy (specifically, positioning B on e8, >>and then bringing the white king back to f4 or g4 area). >> >>It looks to me like black can set up a dynamic (changing) fortress in that event >>(Be8) which holds the draw. >> >>Until Be8 is achieved by white, Black shuffles his Bishop on the long diagonal. >> >>After Be8 is achieved by white (with white K on c6): >> >>STEP 1: Black plays his king to e7 (keeping white king from f6 entry) after >>white king leaves c6 to go to b5 to return to kingside; then >> >>A. While both g5 & g6-pawns still exist: >> >>Corresponding squares for black Bishop (BB) to go to, for each white king (WK) >>square: >>WK BB >>f5 g7 >>h5 g7 >>[Thus white can't sac while his king is on f5 or h5, since BB will block the >>g-pawns. White's king must be *behind* the g5 pawn (not beside it), prior to >>sac of g6-pawn.] >> >>e4 e5 or h8 (not g7) >>f4 e5+ or h8 >>g4 e5 or h8 >>h4 e5 or h8 >> >>B. White sac's the g6-pawn with g6-g7 (while white king starts *behind* >>g5-pawn): >> >>WK BB >>g7 xg7 >>f5 b2 or c3 (long diagonal) >>h5 b2 or c3 (long diagonal) >>g6 c1 or d2 (attack g5) >>h6 c1 or d2 (pin g5) >> >>after any g5-g6 push, Black easily gets to g7, keeping out the white king from >>h6 or f6. >> >>So, where is the forced win, with Be8? >> >>--Steve > > >[D]3kB3/2pP2b1/3p2P1/3P2P1/4K3/8/8/8 w - - > > >When this position is reached then ... >1. Kf4 Ke7 2. Kf5 Bd4 3. g7 I see now. The above position does not have to be forced. Black can shuffle his bishop about, saving a tempo. Here's a line with the Ba4 technique that works. This seems more natural than the Be8 method. 1. Kc6 Be5 2. Bc2 Bg7 3. Ba4 Be5 4. Kb7 Bg7 5. Ka6 Be5 6. Ka5 Bc3+ 7. Kb5 Bb2 8. Kc4 Be5 9. Kd3 Bg7 10. Ke4 Ke7 11. Kf5
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