Author: Terry McCracken
Date: 07:49:00 04/08/02
Go up one level in this thread
On April 08, 2002 at 09:45:43, Martin Giepmans wrote: >On April 07, 2002 at 15:48:22, Terry McCracken wrote: > >>Here's an Endgame that should make _all_ chess engines really work! >> >>Fritz 7 sees the draw but doesn't understand the loss after 1.Qe8+..Qf8?? >> >>Played by Mieses-NN 1903. Mieses won after Qf8??, I'll give the main line. >> >> >>1.Qe8+ Qf8 2.h5 Nf7 3.Kc2 Nd8 4.Kc3 Nf7 5.a4 Nd8 6.Kc4 Nf7 7.Kd5 Nd8 8.b4 Nf7 >>9.Kc6 Nd8+ 10.Kc7 Line >> >>After Qe8+..Kh7! is correct. After 2.Qxd8...Qd2 will draw with perpetual check. >> >>[D]3n2k1/p2P2p1/1p6/7Q/5q1P/8/PP6/1K6 w - - >> >>Terry > >I get this: > >SpiderChess (amd 1200) >05 00:00:00 + 0.77 H5-E8 F4-F8 B1-C2 G7-G6 E8xF8 G8xF8 >06 00:00:00 + 0.33 H5-E8 F4-F8 B1-C2 G7-G6 E8xG6 G8-H8 C2-D3 >07 00:00:00 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3 > D5xA2 >08 00:00:00 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3 > D5-E5 C3-B4 E5xB2 B4-C4 >09 00:00:02 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3 > D5-E5 C3-D3 E5-F5 D3-C4 >10 00:00:11 + 0.10 H5-E8 G8-H7 E8xD8 F4-F5 B1-C1 F5-C5 C1-D2 C5-D5 D2-C3 > D5-E5 C3-D3 E5-F5 D3-C4 F5-F7 C4-B5 > >(score +0.10 means that the engine thinks that it is probably a perpetual) > >After Qe8 Qf8 the score rises immediately: >05 00:00:00 + 0.75 B1-C2 D8-F7 C2-D3 G7-G5 E8xF8 G8xF8 >06 00:00:00 + 0.79 B1-C2 D8-B7 C2-D3 G7-G5 E8xF8 G8xF8 >07 00:00:00 + 0.61 B1-C2 G7-G5 E8-G6 G8-H8 G6-H5 H8-G7 H5xG5 G7-H7 C2-D3 >08 00:00:00 + 0.65 B1-C2 G7-G5 H4xG5 G8-G7 E8xF8 G7xF8 G5-G6 F8-G7 C2-D3 > G7xG6 >09 00:00:01 + 0.45 B1-C2 G7-G6 E8xG6 G8-H8 G6-E8 H8-G7 E8-E5 G7-G8 E5-G5 > G8-H7 C2-C3 F8-F3 C3-B4 D8-C6 B4-B5 >10 00:00:05 + 0.55 B1-C2 G7-G6 E8xG6 G8-H8 G6-E8 H8-G7 E8xF8 G7xF8 H4-H5 > F8-E7 H5-H6 D8-F7 D7-D8D F7xD8 H6-H7 >11 00:00:11 + 0.70 B1-C2 D8-F7 H4-H5 B6-B5 C2-D3 B5-B4 D3-D4 B4-B3 A2xB3 > G7-G5 >12 00:00:48 + 0.86 B1-C2 B6-B5 H4-H5 A7-A6 C2-D3 A6-A5 D3-E4 A5-A4 B2-B3 > A4xB3 A2xB3 G7-G5 >13 00:01:44 + 0.88 B1-C2 A7-A5 H4-H5 A5-A4 C2-D3 B6-B5 D3-E4 D8-F7 E4-D4 > A4-A3 B2xA3 G7-G5 > >Apparently this is mainly eval, allthough the last pv begins to look right ;) > >Cheers, >Martin I'm surprised SpiderChess considers 1..Kh7! It is the _only_ move that survives, and it does indeed looks like it wants to draw with perpetual! It may be the only engine that does! 1..Qd2 also ensures perpetual and draws faster I believe. When you feed it 1..Qf8?, it still has problems seeing the loss, but does see White is better, which is more than I can say for the top commercial programmes. But it doesn't play 2.h5! straight away and I think that White can't win if it isn't played immeadiatly after 1..Qf8? 1.Qe8+..Qf8? 2.Kc2?..g6! and it appears to be a draw with Qxg6+..kh7= with another perpetual. However I haven't dug real deep here. I think you miss the win with White and let Black go. 1.Qe8+..Qf8? 2.h5! ++/- and White will win. Still your eval is very good for finding perpetuals:o) Let SpiderChess work much longer and see if it changes 2.Kc2? to 2.h5! sealing Black's fate. Terry
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