Author: Ricardo Gibert
Date: 00:29:02 01/22/01
Go up one level in this thread
On January 22, 2001 at 03:19:37, Uri Blass wrote: >On January 22, 2001 at 03:06:09, Uri Blass wrote: > >>On January 22, 2001 at 02:10:07, Howard Exner wrote: >> >>>Bf6 draws. Does any program snare this one? >>> >>>[D]r7/4p3/7K/p4p1P/6pk/5Pp1/PB4P1/8 >>> >>>1. Bf6+ exf6 2. f4 Rh8+ 3. Kg7 Rxh5 4. a4 * >>> >>>The rook cannot escape its prison. >> >>1)This position exposes a bug in Deep Fritz. >> >>Deep Fritz cannot see the draw after 4.a4 and only after 4...Rg5+ 5.Kh8 Kh5 >>6.Kh7 Rg6 7.Kh8 Rh6+ 8.Kg7 it suddenly see the draw. >> >>Does Fritz6 suffers from the same bug? >> >>2)Deep Fritz has no problem to see 1.Bf6+ in a few seconds but not with the >>correct 0.00 >> >> >>Uri > >I see that the bug is null move bug because Deep Fritz with selectivity=0 has no >problem to see the draw. > >Deep Fritz cannot find 4.a4 in the default setting so inspite of the fact that >it has no problem to see Bf6+ it cannot solve the position with selectivity=2. > >Uri This makes sense. The solution posted by H. Exner is incomplete and there are at least a couple of zugzwangs further down (17th ply is one).
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