Author: Heiner Marxen
Date: 12:08:22 12/30/02
Go up one level in this thread
On December 30, 2002 at 13:26:41, Uri Blass wrote: >On December 30, 2002 at 10:55:55, Lieven Clarisse wrote: > >>On December 30, 2002 at 10:50:12, Heiner Marxen wrote: >> >>>On December 29, 2002 at 14:36:05, Heiner Marxen wrote: >>> >>>>On December 28, 2002 at 11:04:05, Dieter Buerssner wrote: >>>> >>>>>On December 27, 2002 at 18:12:09, Heiner Marxen wrote: >>>>> >>>>>>On December 27, 2002 at 17:48:52, David Rasmussen wrote: >>>>>> >>>>>>>b2r2kr/p1pqb1p1/1p5p/4p3/2P1N1P1/1P2Q3/P3P2P/4KRR1 b - - 0 1 >>>>>>You mean, black mates white? >>>>>>According to Chest not within 8 moves. >>>>>>I've started another run with depth=10. We'll see. >>>>>> >>>>>>If you have some line you think to be the best, I could try to prove >>>>>>from there. >>>>> >>>>>Perhaps Chest can prove a mate after >>>>> >>>>>1...Bh4+ 2. Rg3 Qd1+ 3. Kf2 Rf8+ 4. Qf3 Qd4+ 5. Kg2 >>>>> >>>>>(After 5. Ke1 it is mate in 10 or faster, so this should also be possible?) >>>> >>>>[D]b4rkr/p1p3p1/1p5p/4p3/2PqN1Pb/1P3QR1/P3P1KP/5R2 b - - >>>>I've started depth 10 from there. >>>>Will need 2 hours or more (hard to guess, EBF appears to be unstable). >>>> >>>>Cheers, >>>>Heiner >>> >>>After 16.2 hours (Athlon 1500+, 128 MB hash) Chest announces "mate in 10" >>>here, with Bxe4 as unique solution key. >>>I'm still waiting for PV and solution tree... the hash has been overrun >>>severely. >>> >>>Cheers, >>>Heiner >> >> >>Thx for posting, what is white answer after bxe4? >> >>regards, >> >>lieven. > >White has no good answer > >The threat of black is h5 with mate in 9 and white has no defence >that does not allow another mate in at most 9 moves. > >I expect pv that begins with h5 a3 but it is hard to know because >I believe that there are more than one move that does not allow black to >give mate in 8 moves. Your analysis matches the output of Chest. Here is its PV PV: Bxe4 c5 h5 h3 Bxf3+ Rfxf3 Bxg3 Rxf8+ Kxf8 Kxg3 Qf4+ Kg2 hxg4 h4 Rxh4 e3 Rh2+ Kg1 Qf2# In the refutation table we have: refu 19: Bxe4 c5 [ 8-] solu 1: Qxe4 [ 7+] solu 3: g5 [ 8+] solu 4: c5 [ 9+] solu 5: Rh3 [ 8+] solu 6: Rh1 [ 7+] solu 7: Re1 [ 7+] solu 8: Rc1 [ 8+] solu 9: h3 [ 8+] solu 10: e3 [ 8+] solu 11: b4 [ 9+] solu 12: a3 [ 9+] solu 13: a4 [ 9+] solu 14: Rg1 [ 8+] solu 15: Kh3 [ 9+] solu 16: Rd1 [ 6+] solu 17: Rb1 [ 7+] solu 18: Ra1 [ 7+] solu 19: Kh1 [ 8+] solu 20: Rf2 [ 9+] i.e. any of a3, a4, b4 and c5 yields the same result, and there is nothing better. Kh3 and Rf2 are equally good (or bad). Chest could have picked any of these instead of c5 for its PV. Cheers, Heiner
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