Author: John Merlino
Date: 15:47:12 05/31/05
Go up one level in this thread
On May 31, 2005 at 18:24:33, Richard Pijl wrote: >I've been using the arasan testsuites quite a lot as they contain a nice mix of >different type of positions. Today I was looking at a position that was always >solved by the Baron in 30 seconds, but not anymore by the latest test version. >I'm talking about the position with id Arasan.81: >[D]1B4k1/5p2/K5p1/7p/P4P2/5P2/8/6n1 b - - >Bestmove is said to be f5, to block the bishop from stopping the black pawn on >h5 from queening. This seems to be confirmed by many engines with about a draw >score. But now, after an initial drawish score, the Baron shows a show of minus >1 pawn in a second, quickly decreasing to - 3 pawns for f5, later switching to >Nxf3 with a similar score. Somehow f5 doesn't seem to be that good. >Just to be sure I also checked with Ruffian, and also Ruffian shows a declining >score for 1..f5, although it needs a little more time to see that. >One line seems to be 1..f5 2.Ba7 Nxf3 (or 2..Ne2 3.Bf2) 3.Bf2 h4 4.Bxh4 and the >a-pawn queens as the king and knight are too far away, e.g 4..Nxh4 5.a5 (5..Nf3 >6.Kb6!) Ng2 6.Kb5 Nxf4 7.a6 Nd5 8.a7 Nc7 9.Kc6 Na8 10.Kb7 >Is there anyone that has a drawing(winning?) line for black after 1..f5? >bye, >Richard. The King appears to agree with you. Here is what CM9_R1 says on an AMD 2500: Time Depth Score Positions Moves 0:00 1/7 -0.80 10271 1...Nxf3 2.Kb7 h4 3.a5 h3 4.f5 h2 5.Bxh2 Nxh2 6.fxg6 fxg6 0:00 1/8 -0.80 14258 1...Nxf3 2.Kb7 h4 3.a5 h3 4.f5 h2 5.Bxh2 Nxh2 6.fxg6 fxg6 0:00 2/9 -0.57 23410 1...Nxf3 2.Kb7 h4 3.a5 h3 4.f5 h2 5.Bxh2 Nxh2 6.fxg6 fxg6 7.a6 g5 0:01 3/10 0.28 74344 1...Nxf3 2.a5 h4 3.Kb7 h3 4.f5 Ng5 5.fxg6 fxg6 6.a6 Nf3 0:02 3/10 -0.66 130015 1...h4 2.a5 f5 3.Kb5 h3 4.a6 h2 5.a7 h1=Q 6.a8=Q Qxf3 7.Qa2+ Kf8 8.Bd6+ Kg7 0:02 4/11 -0.27 187762 1...h4 2.a5 Nxf3 3.Kb7 f5 4.a6 h3 5.a7 h2 6.Be5 h1=Q 7.a8=Q+ Kf7 8.Qa2+ Kf8 9.Qd5 0:04 5/12 0.00 600381 1...h4 2.f5 Nxf3 3.fxg6 h3 4.gxf7+ Kxf7 5.Kb7 Ke6 6.Bg3 h2 7.Bxh2 Nxh2 8.a5 Kd5 0:04 5/12 -0.69 695341 1...f5 2.a5 h4 3.Kb6 h3 4.a6 h2 5.a7 h1=Q 6.a8=Q Qxf3 7.Qa2+ Kh7 8.Qf7+ Kh6 9.Be5 Qe3+ 10.Kb5 0:04 6/13 -0.65 843637 1...f5 2.a5 h4 3.Kb6 h3 4.a6 h2 5.a7 h1=Q 6.a8=Q Qxf3 7.Qa2+ Kh7 8.Qf7+ Kh6 9.Bd6 Ne2 10.Qf6 0:06 7/14 -0.58 1346266 1...f5 2.Ba7 Nxf3 3.a5 h4 4.Bf2 h3 5.Bg3 g5 6.fxg5 Nxg5 7.Kb7 Ne4 8.Bh2 Nc5+ 9.Kb8 0:07 8/15 -0.12 1929788 1...f5 2.Ba7 Nxf3 3.a5 h4 4.Bf2 h3 5.Bg3 Nd2 6.Kb6 Nc4+ 7.Kb5 Nxa5 8.Kxa5 Kf7 9.Bh2 Ke6 0:14 9/16 0.21 4257961 1...f5 2.Ba7 Nxf3 3.a5 h4 4.Bf2 h3 5.Bg3 Kf7 6.Kb7 Nd4 7.a6 Nb5 8.Kb6 Nd6 9.Bh2 0:37 10/17 0.39 12712030 1...f5 2.Ba7 Nxf3 3.a5 h4 4.Bf2 h3 5.Bg3 g5 6.Kb7 gxf4 7.Bxf4 Nd4 8.a6 Nb5 9.Kb6 Nc3 10.a7 Nd5+ 11.Kb7 1:21 11/18 0.93 28271894 1...f5 2.Ba7 Nxf3 3.a5 h4 4.Bf2 h3 5.Bg3 Nd2 6.Kb5 Ne4 7.a6 Nd6+ 8.Kc6 Nc8 9.Kc7 Na7 10.Kb7 Nb5 11.Bf2 3:53 12/19 1.81 79405218 1...f5 2.Ba7 Nxf3 3.Bf2 Nd2 4.Kb5 Nb3 5.Kb4 Nc1 6.a5 Ne2 7.a6 Nxf4 8.Bg3 Ne2 9.a7 Nxg3 10.a8=Q+ Kg7 11.Qg2 h4 All other options for Black appear to be even worse. jm
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