Author: Mark Young
Date: 07:10:12 02/21/00
Go up one level in this thread
On February 20, 2000 at 22:07:48, Jeff Anderson wrote: >On February 20, 2000 at 21:36:59, Imran Hendley wrote: > >>On February 20, 2000 at 21:13:51, Imran Hendley wrote: >> >>>On February 20, 2000 at 21:01:38, Jeff Anderson wrote: >>> >>>>Here is a tough position. It is from Marshall's notes of Salwe vs. Marshall. >>>>There are 3 difficult moves in the winning line. The only program I have that >>>>was able to solve it was Little Goliath 2000a. Can your program find the right >>>>move, and see that Black is winning? >>>> >>>[D]r5k1/2p1b1p1/6bp/p4P2/q3pP2/2PnB2P/PP1N4/KR3Q1R b - - 0 26 >>>> >>>>The main line goes 26...Nb4! 27.cxb4 axb4 28.a3 Bf6! 29.Bd4 Bf7! and Black wins. >>>> >>>>Jeff >> >>On my P200MMX LG2000 v2.5 with 7MB Hashtables Combination ON Solves the position >>in 3:28. What does LG2000a do on your system? And does anyone else's program >>solve this position? > >The position is not as difficult as I thought it was. On my computer it took >LGoliath 2000a just over three minutes to find 26...Nb4, but other programs like >Fritz and Nimzo have found it given sufficient time too. Curiously, none of the >programs were able to tell that Black was winning after the move Nb4, instead >their evals still gave the edge to White, or evaluated the position >approximately equal, but I'm sure given another couple ply they would see that >Nb4 was not only the best move but the winning move. > >Jeff Fritz was able to find the correct move in short order, and show a black advantage. I tried this position on other program and they all did much worse then Fritz 6a. The other program took many minutes to find the correct move if at all. I am not sure why your Fritz did not see a black advantage. New position r5k1/2p1b1p1/6bp/p4P2/q3pP2/2PnB2P/PP1N4/KR3Q1R b - - 0 1 Analysis by Fritz 6: 1...Qa4xa2+ +- (5.31) Depth: 1/3 00:00:00 1...Qa4xa2+ 2.Ka1xa2 Bg6xf5 +- (8.44) Depth: 1/4 00:00:00 1...Bg6xf5 +- (2.84) Depth: 1/4 00:00:00 1...Bg6xf5 ² (0.62) Depth: 1/4 00:00:00 1...Bg6xf5 2.Rh1-g1 ± (0.84) Depth: 2/4 00:00:00 1...Bg6xf5 2.b2-b3 Qa4-c6 ² (0.66) Depth: 3/9 00:00:01 1...Bg6xf5 2.b2-b3 Qa4-c6 3.Nd2-c4 ± (0.75) Depth: 4/12 00:00:01 1kN 1...Bg6xf5 2.Rh1-g1 Ra8-b8 3.Qf1-g2 Be7-f6 ² (0.69) Depth: 5/17 00:00:01 9kN 1...Bg6xf5 2.Rh1-g1 Ra8-b8 3.Qf1-g2 Be7-f6 4.Qg2-g3 ± (0.75) Depth: 6/21 00:00:01 18kN 1...Bg6xf5! ² (0.44) Depth: 7/22 00:00:02 126kN 1...Bg6xf5 2.Be3-d4 c7-c5 3.Bd4-e3 Be7-f6 4.Rh1-g1 Ra8-b8 5.Qf1-g2 ² (0.53) Depth: 8/24 00:00:03 351kN 1...Bg6xf5 2.Be3-d4 c7-c5 3.Bd4-e5 Ra8-d8 4.Qf1-g2 g7-g6 5.Rh1-d1 Rd8-e8 ² (0.50) Depth: 9/25 00:00:04 856kN 1...Bg6xf5 2.Be3-d4 c7-c5 3.Bd4-e5 Ra8-e8 4.Rh1-g1 Be7-f8 5.b2-b3 Qa4-d7 6.Qf1-e2 ² (0.62) Depth: 10/27 00:00:08 1987kN 1...Bg6-f7 ² (0.59) Depth: 10/27 00:00:10 2577kN 1...Bg6-f7 2.b2-b3 Qa4-c6 3.Be3-d4 Ra8-d8 4.Bd4xg7 Kg8xg7 5.Qf1-g2+ Kg7-h7 6.Nd2xe4 = (0.22) Depth: 10/27 00:00:12 2926kN 1...Bg6-f7 2.b2-b3 Qa4-c6 3.Be3-d4 Ra8-d8 4.Nd2-c4 Bf7xc4 5.b3xc4 Be7-f6 6.Bd4-e5 ² (0.31) Depth: 11/27 00:00:15 3874kN 1...Bg6-f7 2.b2-b3 Qa4-c6 3.Be3-d4 Ra8-d8 4.Nd2-c4 Bf7xc4 5.b3xc4 Be7-f6 6.Bd4-e5 = (0.03) Depth: 12/29 00:00:26 7443kN 1...Bg6-f7 2.b2-b3 Qa4-c6 3.Be3-d4 Ra8-d8 4.Nd2-c4 Bf7xc4 5.b3xc4 Be7-f6 6.Bd4-e5 = (0.03) Depth: 13/31 00:00:47 14324kN 1...Nd3-b4 = (0.00) Depth: 13/31 00:01:15 23217kN 1...Nd3-b4! ³ (-0.31) Depth: 14/32 00:01:49 34482kN 1...Nd3-b4! 2.c3xb4 a5xb4 3.a2-a3 Be7-f6 4.Be3-d4 Bg6-f7 5.Qf1-d1 Bf6xd4 6.Qd1xa4 µ (-0.75) Depth: 14/37 00:02:37 48069kN 1...Nd3-b4 2.c3xb4 a5xb4 3.a2-a3 Be7-f6 4.Be3-d4 Bg6-f7 5.Qf1-d1 Bf6xd4 6.Qd1xa4 µ (-0.78) Depth: 15/36 00:06:45 81250kN 1...Nd3-b4! µ (-1.09) Depth: 16/35 00:09:58 147670kN 1...Nd3-b4! 2.c3xb4 a5xb4 3.a2-a3 Bg6-f7 4.Rb1-c1 Be7-f6 5.Ka1-b1 b4xa3 6.Rc1-c4 -+ (-4.75) Depth: 16/43 00:15:27 261191kN 1...Nd3-b4! -+ (-5.06) Depth: 17/40 00:22:18 402734kN 1...Nd3-b4! 2.c3xb4 a5xb4 3.a2-a3 Bg6-f7 4.Rb1-c1 Be7-f6 5.Ka1-b1 b4xa3 6.Rc1-c4 -+ (-5.81) Depth: 17/48 00:30:07 568174kN 1...Nd3-b4 2.c3xb4 a5xb4 3.a2-a3 Bg6-f7 4.Rb1-c1 Be7-f6 5.Ka1-b1 b4xa3 6.Rc1-c4 -+ (-5.78) Depth: 18/42 00:45:25 889570kN 1...Nd3-b4 2.c3xb4 a5xb4 3.a2-a3 Bg6-f7 4.Rb1-c1 Be7-f6 5.Ka1-b1 b4xa3 6.Rc1-c4 -+ (-6.06) Depth: 19/45 01:37:16 1978116kN 1...Nd3-b4 2.c3xb4 a5xb4 3.a2-a3 Bg6-f7 4.Rb1-c1 Be7-f6 5.Ka1-b1 b4xa3 6.Rc1-c4 -+ (-6.16) Depth: 20/45 03:50:06 4760002kN 1...Nd3-b4! -+ (-6.47) Depth: 21/47 07:41:48 9601011kN (Young, 21.02.2000)
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