Author: Uri Blass
Date: 04:25:04 08/21/03
Go up one level in this thread
On August 21, 2003 at 07:18:47, Uri Blass wrote: >On August 21, 2003 at 07:06:20, Omid David Tabibi wrote: > >>On August 21, 2003 at 06:12:12, Jouni Uski wrote: >> >>>[D]8/1p6/1Pp2N1q/p1Ppk2p/P3p3/3PPpPp/3K1P1P/1R6 w - - >>> >>>From CSS forum: Machine should, within a million hours, be able to find the draw >>>in this position (with Ng4+). But Shredder 7.04 found it in one second!! >>> >> >>It is not a draw. The black queen will penetrate into the white cvamp via a6. >>For the past year I've been working on endgame blockage detection. I noticed >>that Shredder has some very limited form of blockage detection, but it is very >>inaccurate, and in many positions I tried, that inaccurate blockage detection >>wreaked havoc to the search tree. > >Wrong > >It is a draw >I also believed that it is not a draw but trying to win it >against shredder I got the following game > >[Event "?"] >[Site "?"] >[Date "????.??.??"] >[Round "?"] >[White "New game"] >[Black "?"] >[Result "*"] >[SetUp "1"] >[FEN "8/1p6/1Pp2N1q/p1Ppk2p/P3p3/3PPpPp/3K1P1P/1R6 w - - 0 1"] >[PlyCount "11"] > >1. Ng4+ hxg4 2. d4+ Ke6 3. Rh1 Qf8 4. Ke1 Qa8 5. Kf1 Qa6+ 6. >Kg1 and black cannot make progress > >Uri Here is some analysis of shredder in a non draw position Shredder believes that black advantage is very small until seeing the win by search. I believe that shredder's score for maybe fortress position is too small and +1 for black is more realistic for a position that may be in significant part of the cases a win for the stronger side. New game 8/1p6/1Pp2N1q/p1Ppk2p/P3p3/3PPpPp/2K2P1P/1R6 w - - 0 1 Analysis by Shredder 7.04: 1.dxe4 Kxf6 2.exd5 -+ (-2.38) Depth: 1/2 00:00:00 1.dxe4 Kxf6 2.exd5 -+ (-2.97) Depth: 1/3 00:00:00 1.dxe4 Qxf6 2.exd5 Kxd5 -+ (-4.95) Depth: 1/4 00:00:00 1.Nxe4 dxe4 -+ (-4.70) Depth: 1/4 00:00:00 1.Nxe4 dxe4 -+ (-4.70) Depth: 1/4 00:00:00 1.Nd7+ Kf5 -+ (-2.24) Depth: 1/4 00:00:00 1.Nd7+ Kf5 -+ (-1.55) Depth: 1/4 00:00:00 1.Nd7+ Kf5 -+ (-1.55) Depth: 1/4 00:00:00 1.Nd7+ Ke6 2.Re1 -+ (-1.82) Depth: 2/6 00:00:00 1.Nd7+ Ke6 2.dxe4 Kxd7 3.exd5 -+ (-2.38) Depth: 2/6 00:00:00 1.Nd7+ Ke6 2.Nb8 -+ (-2.36) Depth: 2/6 00:00:00 1.Nd7+ Ke6 2.Nb8 exd3+ 3.Kc3 -+ (-3.12) Depth: 3/9 00:00:00 1.Nd7+ Ke6 2.Nb8 exd3+ 3.Kc3 -+ (-3.62) Depth: 3/11 00:00:00 1.Nd7+ Ke6 2.Nb8 exd3+ 3.Kc3 -+ (-3.62) Depth: 3/11 00:00:00 1.Ne8 Qf6 2.Nxf6 -+ (-3.61) Depth: 3/11 00:00:00 1.Ne8 exd3+ 2.Kc3 Ke4 -+ (-3.28) Depth: 3/11 00:00:00 1.Ne8 Qd6 2.cxd6 exd3+ 3.Kxd3 -+ (-3.03) Depth: 4/11 00:00:00 1.Ne8 exd3+ 2.Kc3 Qh7 3.Nd6 -+ (-2.87) Depth: 4/11 00:00:00 1.Ne8 exd3+ 2.Kc3 h4 3.g4 Qg6 -+ (-3.03) Depth: 5/13 00:00:00 1.Ne8 exd3+ 2.Kc3 d2 3.Rd1 Qg6 4.Nd6 -+ (-3.00) Depth: 6/16 00:00:00 13kN 1.Ne8 exd3+ 2.Kc3 Qh7 3.Nd6 d2 4.Rd1 -+ (-3.07) Depth: 7/16 00:00:00 26kN 1.Ne8 exd3+ 2.Kc3 Qh7 3.Nd6 Qf5 -+ (-2.82) Depth: 8/21 00:00:00 50kN 1.Ne8 exd3+ 2.Kc3 h4 3.Nd6 Qg7 4.gxh4 Qh7 5.h5 -+ (-2.65) Depth: 8/21 00:00:00 66kN 1.Ne8 exd3+ 2.Kc3 Qg6 3.Nd6 Qg4 4.e4 Qd7 5.Kxd3 dxe4+ 6.Ke3 -+ (-2.65) Depth: 9/22 00:00:01 149kN 1.Ne8 exd3+ 2.Kc3 Qg6 3.Nd6 Qg4 4.e4 Qg7 5.Nf5 Qg6 6.Rb2 -+ (-2.90) Depth: 10/22 00:00:02 219kN 1.Ne8 exd3+ 2.Kc3 Qg6 3.Nd6 Qg4 4.e4 Qg7 5.Kxd3 dxe4+ 6.Kc4 Qd7 -+ (-2.92) Depth: 10/25 00:00:02 290kN 1.Ng4+ Kf5 2.Nxh6+ Ke6 -+ (-2.91) Depth: 10/25 00:00:02 316kN 1.Ng4+ Kf5 2.Nxh6+ Ke6 3.dxe4 h4 4.gxh4 dxe4 5.Rd1 Ke5 6.Kc3 -+ (-2.56) Depth: 10/25 00:00:02 316kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Kc3 Qf8 4.Rd1 Qa8 5.Kd2 Kf5 6.Kc3 Qa6 = (-0.15) Depth: 10/25 00:00:02 390kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kc3 Qe8 5.Kb3 Kd7 6.Ka3 Qg6 7.Rb1 = (-0.14) Depth: 11/25 00:00:03 414kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kb3 Kd7 5.Kc3 Qf7 6.Kb3 Ke6 = (-0.14) Depth: 12/25 00:00:03 465kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kb3 Kd7 5.Kc3 Qf7 6.Kb3 Ke6 = (-0.14) Depth: 13/25 00:00:04 559kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kb3 Kd7 5.Kc3 Qf7 6.Kb3 Ke6 = (-0.14) Depth: 14/25 00:00:05 722kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kb3 Kd7 5.Kc3 Qf7 6.Kb3 Qe8 7.Ka3 Ke6 8.Rb1 Kf5 9.Re1 = (-0.15) Depth: 15/25 00:00:06 930kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kb3 Kd7 5.Kc3 Qf7 6.Kb3 Qe8 7.Ka3 Ke6 8.Rb1 Kf5 9.Rb2 Kg6 = (-0.14) Depth: 16/25 00:00:08 1374kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qg6 4.Kb3 Kd7 5.Rb1 Qf7 6.Re1 = (-0.14) Depth: 17/25 00:00:11 2079kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qf8 4.Kc3 Qa8 5.Rd2 Qa6 6.Ra2 Qc4+ 7.Kb2 Qf1 8.Kc2 Qxf2+ 9.Kc3 Qxe3+ 10.Kc2 Qxd4 11.Ra1 Qxa1 ³ (-0.39) Depth: 18/25 00:00:18 3513kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Rd1 Qf8 4.Kc3 Qa8 5.Rd2 Qa6 6.Ra2 Qc4+ 7.Kb2 Qf1 8.Kc2 Qxf2+ 9.Kc3 Qxe3+ 10.Kc2 Qxd4 11.Ra1 Qxa1 µ (-0.89) Depth: 18/25 00:00:18 3699kN 1.Ng4+ hxg4 2.d4+ Ke6 3.Kd2 Qf8 4.Ke1 Qa8 5.Kf1 Qa6+ 6.Kg1 Qc4 7.Re1 Qxa4 8.Rb1 -+ (-9.21) Depth: 18/38 00:00:35 7365kN 1.Nd7+ Ke6 2.Nb8 exd3+ 3.Kd2 Qf8 4.Nxc6 bxc6 5.Rb2 Qxc5 6.Kxd3 Qxe3+ 7.fxe3 Ke5 -+ (-9.20) Depth: 18/42 00:01:22 16520kN 1.Nd7+ Ke6 2.Nb8 exd3+ 3.Kd2 Qf8 4.Nxc6 bxc6 5.Rb2 Qxc5 6.Kxd3 Qxe3+ 7.fxe3 Ke5 8.Kc3 Kd6 -+ (-8.85) Depth: 18/42 00:01:31 18559kN (Blass, Tel-Aviv 21.08.2003) Uri
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