Author: Mike Hood
Date: 04:31:10 01/08/04
Go up one level in this thread
On January 07, 2004 at 10:44:36, Robert Hyatt wrote: >On January 07, 2004 at 05:26:58, Mike Hood wrote: > >>On January 07, 2004 at 00:20:17, K. Burcham wrote: >> >>> >>>Steve Maughan, big book of combinations >>> >>>Tibensky - Franzen >>>Find Kh6 >>> [D] 1r3rk1/b1pR1p2/p3p1p1/2q1P1Kp/P1N2P2/1P1Q2P1/7P/3R4 w - - >> >>This is on my humble Pentium III-733. Patzer was the first engine I tried, >>because it seems to be skilful at finding the right move in closed positions. >> >>Analysis by Patzer 3.11: >> >>1.Qxg6+ >> -+ (-10.00) Depth: 1 00:00:00 >>1.Qf3 >> ² (0.42) Depth: 1 00:00:00 >>1.Qf3 Bb6 >> µ (-0.98) Depth: 2 00:00:00 >>1.Qf3 >> µ (-0.96) Depth: 2 00:00:00 >>1.Kh4 >> ³ (-0.57) Depth: 2 00:00:00 >>1.Kh4 >> = (-0.18) Depth: 3 00:00:00 >>1.Qf3 >> = (-0.06) Depth: 3 00:00:00 >>1.Qf3 a5 >> µ (-0.75) Depth: 4 00:00:00 1kN >>1.g4 hxg4 2.Kxg4 a5 3.Qh3 Rbe8 >> = (-0.04) Depth: 4 00:00:00 9kN >>1.g4 hxg4 2.Kxg4 Ra8 3.Qg3 >> = (0.17) Depth: 5 00:00:00 36kN >>1.g4 hxg4 2.Kxg4 a5 3.Qh3 Rfe8 4.Rxf7 Kxf7 5.Qh7+ >> = (-0.06) Depth: 6 00:00:01 115kN >>1.Qf3 Bb6 2.g4 hxg4 3.Qg3 a5 >> = (-0.03) Depth: 6 00:00:02 152kN >>1.Kh4 Qf2 2.Rd2 Qc5 3.Rd1 >> = (0.00) Depth: 6 00:00:02 167kN >>1.Kh6 >> ² (0.51) Depth: 6 00:00:03 284kN >>1.Kh6 a5 2.Nxa5 Qxa5 3.Qxg6+ fxg6 4.Rg7+ >> ² (0.56) Depth: 7 00:00:04 376kN >>1.Kh6 a5 2.Nxa5 Qxa5 3.Qxg6+ fxg6 4.Rg7+ Kh8 5.Rh7+ Kg8 6.Rg7+ >> ² (0.56) Depth: 8 00:00:05 497kN >>1.Kh6 a5 2.Nxa5 Qxa5 3.Qxg6+ fxg6 4.Rg7+ Kh8 5.Rh7+ >> ² (0.56) Depth: 9 00:00:08 841kN >>1.Kh6 Rfc8 2.Rxf7 Kxf7 3.Qxg6+ Ke7 4.Qf6+ Ke8 5.Nd6+ cxd6 6.Rxd6 Rb7 7.Qh8+ Ke7 >>8.Qf6+ >> ² (0.56) Depth: 10 00:01:15 11987kN > > >It isn't seeing what it is supposed to see. Kh6 is a big tactical win. Here >for some reason, patzer simply can't see any way for white to improve after Kh4, >which is strange as white is better. But since it drops to draw for Kh4, Kh6 >is chosen for the wrong reason... Most programs evaluate Kh4 and Kh6 as nearly >the same until they notice that Kh6 wins big material after a pretty deep >search. Maybe you're right, Robert, that Patzer is choosing the right move for the wrong reason. When setting up Patzer to analyse several lines simultaneously I saw that it rated several other moves as almost as good as Kh6 (Nd2, Na5, h3, g4, b4). Amusingly, when Patzer gets to search depth 11 it starts accessing the tablebases. I've included the next two lines of analysis below. I have all the 5-piece EGTBs, so in the 22 moves Patzer must have found a line with 17 captures :) 1.Kh6 ± (0.90) Depth: 11 00:03:03 28901kN, tb=4 1.Kh6 Qc6 2.Na5 Qa8 3.Qxa6 Qf3 4.Qd3 Qg4 5.Nc6 h4 +- (1.54) Depth: 12 00:22:48 195857kN, tb=17
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