Author: Uri Blass
Date: 16:10:48 09/27/01
Go up one level in this thread
On September 27, 2001 at 18:02:03, Dann Corbit wrote: >On September 27, 2001 at 17:47:47, Robert Hyatt wrote: > >>On September 27, 2001 at 17:33:58, Roy Eassa wrote: >> >>>On September 27, 2001 at 17:07:23, Andy Serpa wrote: >>> >>>>I am intrigued by this position from an old book: >>>> >>>>[D]rnb2r1k/pp1p2pp/2p1P3/2q1p3/2B3Q1/2N4P/PPP3P1/R1B4K w - - 0 1 >>>> >>>> >>>>In the book, White saves himself with the following manoeuvre: >>>> >>>>1. b4 Qxb4 2. Rb1 Qxc3 3. Bh6 gxh6 4. e7 Re8 5. Rf1 >>>>and white mates in a few moves. >>>> >>>> >>>>I'm curious what a fast computer comes up with in this position... >>> >>> >>>Starting two moves in (I think it's too hard to start at the beginning), after >>>1. b4 Qxb4 2. Rb1 Qxc3: >>> >>>[D]rnb2r1k/pp1p2pp/2p1P3/4p3/2B3Q1/2q4P/P1P3P1/1RB4K w - - 0 1 >>> >>>Here's what I get with Gambit Tiger 2.0 Aggressive on an Athlon 1.2 (in 1 >>>minute, it sees it has a perpetual. In 1.5 minutes, it sees it has an >>>advantage. In 4 minutes, it sees it has a win.): >>> >>>00:00:00.8 -4.14 8 161550 Bd3 Qe1+ Kh2 Qf2 e7 Re8 Bxh7 Rxe7 Bg6 >>>00:00:00.1 -3.24 8 312659 Bd3 >>>00:00:01.7 -3.24 9 391208 Bd3 Qe1+ >>>00:00:01.4 -3.68 9 670505 Bd3 Qc5 Qh4 e4 Qxe4 Qh5 e7 Re8 Ba3 d5 >>>00:00:02.2 -3.02 9 885911 e7 Re8 Bh6 gxh6 Rf1 Qa3 Rf7 Qc1+ Kh2 Qf4+ Rxf4 exf4 >>>00:00:05.0 -2.12 10 2037930 e7 >>>00:00:06.5 -2.12 11 2496977 e7 >>>00:00:11.9 -1.60 11 4422079 e7 Re8 Bd3 d5 Qf3 Nd7 Qf7 Rxe7 Qxe7 Qc5 Qe6 Qf8 Bb2 >>>00:00:14.9 -1.60 12 5492547 e7 Re8 >>>00:00:48.3 -1.36 12 17494341 Bd3 Qe1+ Kh2 Rf1 Bxf1 Qxf1 Ba3 Qf6 e7 Qf7 Rf1 Qg8 >>>Qf5 >>>00:00:55.1 -0.70 12 20234211 Bh6 >>>00:00:57.8 -0.31 12 21078455 Bh6 gxh6 e7 Re8 Rf1 Qa3 Rf7 Qc1+ Kh2 Qg5 Rf8+ Kg7 >>>Rf7+ Kg8 Rf8+ Kg7 >>>00:01:33.7 0.59 13 35309917 Bh6 >>>00:04:00.9 3.84 13 94628156 Bh6 Rg8 e7 Qxc4 Qxc4 d5 Bxg7+ Kxg7 Qh4 Nd7 Qg5+ Kf7 >>>Rf1+ Ke6 Qxg8+ Kxe7 Rf7+ Kd6 >> >> >>I think that is too late to start searching. Qc3 probably loses. Question is, >>is there an alternative that doesn't, such as Qa3 instead. I haven't studied it >>much, but the queen at c3 is locked out of the game which is how white wins. > >After b4, I think Qf2 is white's best move. It's still bad, but not a clear >loser like Qxb4. What are the programs evaluations after b4 Qxb4 that make you sure that Qxb4 is a clear loser? The move Qxc3 is a clear loser after b4 Qxb4 Rb1 and Juniot7 can see a forced mate after these moves. I am less sure about Qxb4. From what I have seen so far, all the programs I have tested >snack on the pawn and have no idea of the trouble in store. They have a big, >fat, positive eval after taking the pawn, even after a nice long think about it. Not all of them Here is Junior7's analysis on a slow p200 New position rnb2r1k/pp1p2pp/2p1P3/2q1p3/1PB3Q1/2N4P/P1P3P1/R1B4K b - - 0 1 Analysis by Junior 7: 1...Qxb4 2.Bd2 dxe6 -+ (-2.10) Depth: 3 00:00:00 1...Qxb4 2.Bd2 b5 3.Be2 Qxg4 4.Bxg4 -+ (-2.06) Depth: 6 00:00:00 6kN 1...Qxb4 2.Bd3 Qxg4 3.hxg4 dxe6 4.Ba3 Rf4 5.Rf1 Rxg4 -+ (-1.87) Depth: 9 00:00:01 218kN 1...Qxb4 2.Bd3 Qxg4 3.hxg4 dxe6 4.Ba3 Rf4 5.Rf1 Rxf1+ 6.Bxf1 Nd7 7.Ne4 -+ (-1.98) Depth: 12 00:00:35 4705kN 1...Qxb4 2.Rb1 Qc5 3.Be3 Qa3 4.Bc1 = (0.00) Depth: 13 00:03:10 25572kN 1...Qd6 2.Qh4 dxe6 3.Bd3 e4 4.Qxe4 g6 5.Bh6 Rf7 6.Qe3 Nd7 ³ (-0.28) Depth: 13 00:04:10 33675kN Uri
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