Author: Ross Boyd
Date: 15:17:28 11/16/04
Go up one level in this thread
On November 16, 2004 at 16:36:19, Kolss wrote: >On November 16, 2004 at 15:37:55, Ross Boyd wrote: > >>On November 16, 2004 at 11:14:11, Kolss wrote: >> >>>On November 16, 2004 at 10:49:31, Alessandro Scotti wrote: >>> >>>>In this position (WAC 213): >>>> >>>>[D]3r1r1k/1b4pp/ppn1p3/4Pp1R/Pn5P/3P4/4QP2/1qB1NKR1 w - - >>>> >>>>the best move is Rxh7+, but is Rxg7 playable too? >>>> >>>>When I experiment with extensions I can get either this: >>>> >>>>Rxg7 Kxg7 Rxh7+ Kxh7 Qh5+ Kg7 Bh6+ Kh8 Bd2+ Kg8 >>>> >>>>or this: >>>> >>>>Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 Bf4+ Kg8 >>>> >>>>both with a zero score. >>> >>>Hello, >>> >>>If I recall right (no program available to check at the moment), Rxg7 is NOT a >>>solution: it only leads to a draw by repetition, while Rxh7+ is a checkmate in >>>something like 16 (or 14). The difference is that after Rxg7 Kxg7 Rxh7+ Kxh7 >>>Qh5+, the black king can go to g8 instead of g7, such that the bishop check on >>>h6 is no longer possible. >>> >>>Please correct me if I am wrong, as I said, I do not have a chess program at >>>hand to check... >>> >>>Best regards - Munjong. >> >> >>TRACE 1.32 RELEASE on an AMD XP 2800 finds mate in 18 in 20 secs: >> 2 00:00 2.264 226.400 -5.89 Bg5 >> 3 00:00 2.772 277.200 -6.14 Bg5 Rxd3 Bf4 >> 3 00:00 2.969 296.900 -6.15 Bg5 Rd5 Qf3 Nxe5 >> 3 00:00 4.578 457.800 -6.14 Be3 >> 3 00:00 5.239 523.900 -5.70 Be3 Nxe5 Bxb6 >> 4 00:00 9.127 912.700 -5.55 Be3 Rxd3 Bxb6 Nd4 >> 4 00:00 10.532 351.066 -5.54 Rxh7+ >> 4 00:00 10.778 359.266 -3.54 Rxh7+ >> 4 00:00 12.323 410.766 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 >> 5 00:00 17.983 449.575 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 Qg6+ >> 6 00:00 32.573 465.328 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 Qg6+ >> 7 00:00 68.743 572.858 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 Qg6+ >> 8 00:00 167.243 643.242 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 Qg6+ >> 9 00:00 319.334 742.637 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 Qg6+ >> 10 00:01 872.326 692.322 0.00 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bc1+ Kg8 Qg6+ Kh8 Qh6+ Kg8 Qg6+ >> 11 00:13 6.639.903 486.796 +0.25 Rxh7+ >> 11 00:15 7.435.234 491.098 +2.25 Rxh7+ >> 11 00:20 9.998.275 484.412 +M18 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bg5+ Kg7 Qh6+ Kf7 Qf6+ Kg8 Qg6+ >> 12 00:27 13.295.440 485.412 +M18 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bg5+ Kg7 Qh6+ Kf7 Qf6+ Kg8 Qg6+ >> 13 00:41 20.550.172 490.574 +M18 Rxh7+ Kxh7 Qh5+ Kg8 Rxg7+ Kxg7 Bh6+ Kh7 >>Bg5+ Kg7 Qh6+ Kf7 Qf6+ Kg8 Qg6+ Kh8 Bf6+ Rxf6 exf6 Qxe1+ >> >>Cheers, >> >>Ross > >Hi, > >You are right (i.e. Trace is... :-) - Ikarus also says +M18 for Rxh7+ (so I was >wrong with the 16 or 14, as it seems). > >Best regards - Munjong. After 2.5 hours and ply 16 finished, TRACE can't find anything shorter. Playing over it I don't think there is a shorter mate either. Ross
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