Author: Joshua Lee
Date: 10:03:39 07/11/01
Go up one level in this thread
>>>>500Mhz Laptop >>>>bm Bxh7+ - NOLOT.EPD >>>> >>>>[D] r3rbk1/ppq2ppp/2b1pB2/8/6Q1/1P1B3P/P1P2PP1/R2R2K1 w - - 0 1 >>>> >>>>Analysis by Fritz 6: >>>> >>>>1.Bxg7-- >>>> µ (-1.16) Depth: 1/3 00:00:00 >>>>1.Bxg7-- Bxg7 >>>> -+ (-2.12) Depth: 1/3 00:00:00 >>>>1.Bxh7+! >>>> -+ (-2.06) Depth: 1/3 00:00:00 >>>>1.b4 a6 2.c4 e5 3.b5 e4 4.Be2 Re6 5.Bg5 Be8 >>>> ² (0.28) Depth: 19/45 07:34:56 11000312kN >>>>1.b4 a6 2.c4 g6 3.Qg5 Ba4 4.Rdc1 Be7 5.c5 Rad8 >>>> = (0.25) Depth: 20/46 24:10:39 35603334kN >>>>1.Bxh7+! >>>> ² (0.28) Depth: 20/49 32:29:19 48172103kN >>>>1.Bxh7+! >>>> ² (0.59) Depth: 21/46 35:24:52 52617477kN >>>> >>>> >>>>my 800Mhz athlon would only shave a few hours off this despite more speed and >>>>256MB for Hash tables instead of 64 for the laptop. >>> >>>What is the winning line ? After Bxh7+ Kxh7 Qh5+ Kg8 Rd4 Bf3! followed by Qxc2 >>>and Qg6 i don't see how white is winning ,only a slight edge perhaps. >>> >>>Pierre >> >>1.Bxh7+ 1...Kxh7 2.Qh5+ Kg8 3.Rd4 gxf6 4.Rg4+ Bg7 5.Qh6 Kf8 6.Rxg7 Be4 7.Qxf6 >>Red8 [7...Rac8 8.Qg5 Bg6 9.Qh6 Qxc2 10.Rxg6+ Ke7 11.Qh4+ Kd7 12.Qd4+] 8.Qg5 +- >> >>Regards, >>Christoph > >But 3....gxf6 is bad i think, better is 3....Bf3 ! . > >Pierre 1. Bxh7+ Kxh7 2. Qh5+ Kg8 3. Rd4 Bf3! you are right about Bf3 and it would indeed take more time for the computer to find all of this but the point is that it found white's best line of play according to Guefeld except Deep Thought has it's own opinion 1. c4 which prevents this very good counterplay see below 4a. gxf3 and in both cases white has initiative +/= 4b. Qxf3 Exeter Chess Club: Trawled from the 'Net From cen.ex.ac.uk!strath-cs!uknet!warwick!slxsys!pipex!howland.reston.ans.net!europa.eng.gtefsd.com!swiss.ans.net!newsgate.watson.ibm.com!hawnews.watson.ibm.com!sawmill!fhh Fri Aug 5 09:37:26 BST 1994 Article: 31130 of rec.games.chess Newsgroups: rec.games.chess Path: cen.ex.ac.uk!strath-cs!uknet!warwick!slxsys!pipex!howland.reston.ans.net!europa.eng.gtefsd.com!swiss.ans.net!newsgate.watson.ibm.com!hawnews.watson.ibm.com!sawmill!fhh From: fhh@watson.ibm.com (Feng-Hsiung Hsu) Subject: Nolot's 11 difficult positions (possible spoilers) Message-ID: Sender: fhh@watson.ibm.com Date: Thu, 28 Jul 1994 18:19:37 GMT Disclaimer: This posting represents the poster's views, not necessarily those of IBM. Nntp-Posting-Host: sawmill.watson.ibm.com Organization: IBM T.J. Watson Research Center Followup-To: rec.games.chess Lines: 251 Sometime ago, the following 11 positions collected by Pierre Nolot were posted to rgc. Pierre claimed that no computers can solve any of them in reasonable time (and no micros in even a few weeks). A long while back, he might be right. At this point, a few of them are solvable even under tournament time control. The ones that we tried overnight are all solvable in a few hours. DT-2 was searching around 3 million nodes/sec during the runs. The time probably would be reduced by 5-30 times for the harder problems if the machine has a better quiescence search. The comments below might be considered spoilers. The first line for each position is in a computer-readable notation. 1 ;r3;q;b1;k/1;b4;p1/;p2;p;r2;p/3;n4/p;n;p1n1n1/6rp/1b3pp1/1b1qr1k1/40 white to move 8 R * - * Q B - K 7 * B * - * - P - 6 P * - P R * - P 5 * - * N * - * - 4 p N P * n * n * 3 * - * - * - r p 2 - b - * - p p * 1 * b * q r - k - a b c d e f g h Source: Kasparov-Karpov, Lyon 1990. Kasparov played Nh6 here. DT-2 agreed with Kasparov's analysis after going down the line given in Informant, but could not find the move on its own in one hour time. When letting it run overnight, it produced Nh6 after 8 hours (but would play it with a 6 hours/move time control; that is, it got first indication that the combination might work after about 6 hours), with the variation 1. Nh6! c3 2. Nf5 cb2 3. Qg4 ... which wins for white. 2 ;r4;r;k1/;p;p1;n1;p1;p/1;n;qP2;p1/2;b1p1b1/4nq2/1b3p2/pp2k2p/2r5/40 White to move 8 R * - * - R K * 7 P P * N * P * P 6 - N Q p - * P * 5 * - B - p - b - 4 - * - * n q - * 3 * b * - * p * - 2 p p - * k * - p 1 * - r - * - * - a b c d e f g h Source: Bronstein-Ljubojevic, Petropolis 1973. Solution is 1. Rc5! Nc5 2. Nf6 Kh8 3. Qh4... Solved under tournament time control (3 minutes/move, plus extra time if the value for the move is unstable). Plays it after 2 minutes. Actually spent 4.5 minutes before the value stabilized to about a piece up. 3 ;r2;q;k2;r/;p;p;p1;b1;p;p/2;n1;p3/3;pp1;n1/3p2;b1/2pb1nn1/pp4pp/r1bqk2r/40 White to move 8 R * - Q K * - R 7 P P P - B - P P 6 - * N * P * - * 5 * - * P p - N - 4 - * - p - * B * 3 * - p b * n n - 2 p p - * - * p p 1 r - b q k - * r a b c d e f g h Source: Smagin-Sahovic, Biel 1990. Solution move is 1. Ng5!. Verified that the move is sound by following the published analysis, but could not play it within one hour time. This is more a positional sac than what would be normally called tactics. 4 ;r1;b1;k;b1;r/1;p1;n1;p;p;p/;p2;p;p;n2/6bb/2;qnp3/2n5/ppp2ppp/r2q1rk1/40 White to move 8 R * B * K B - R 7 * P * N * P P P 6 P * - P P N - * 5 * - * - * - b b 4 - * Q n p * - * 3 * - n - * - * - 2 p p p * - p p p 1 r - * q * r k - a b c d e f g h Source: Keres-Kotov, Budapest 1950. Solution: 1. Ne6 Qe6 2. Nd5 Kd8 3. Bg4. Plays it after 3.8 hours, would play it under 2.5 hour/move time control. 5 ;r2;q;r;b1;k/1;p1;b2;p1/;p2;p;p;n1;p/8/3np3/1bn5/ppp3qp/1k3rr1/40 White to move 8 R * - Q R B - K 7 * P * B * - P - 6 P * - P P N - P 5 * - * - * - * - 4 - * - n p * - * 3 * b n - * - * - 2 p p p * - * q p 1 * k * - * r r - a b c d e f g h Source: Spassky-Petrosian, Moskow 1969. Took 4 hours to find e5!. 1. e5! de5 2. Ne4 Nh5 3. Qg6... More than a piece up. The minimum time control needed to play it is around 2 hours/move. 6 ;r;n;b;q;k2;r/1;p3;p;p;p/;p7/1n;pp;p3/qpp1p1;n1/p4n2/4k;bpp/r1b2b1r/41 Black to move 8 R N B Q K * - R 7 * P * - * P P P 6 P * - * - * - * 5 * n P p P - * - 4 q p p * p * N * 3 p - * - * n * - 2 - * - * k B p p 1 r - b - * b * r a b c d e f g h Source: Melaniuk-Ivanchuk, USSR 1988. Ivanchuk played 1. ... ab5! which appears to be a sound positional sacrifice. Calling this position a tactical one, however, is a little unfair on Pierre's part. Ivanchuk, by the way, could not find the best continuations over the board, but won it anyway due to Melaniuk's inaccurate defence. Could not solve it in one hour. Probably a home preparation. The same move was replayed 3 years later in some random tournament. 7 1;r1;b;k2;r/2r2;p;p;p/;p3;p3/1;b2p2;q/4qp2/4n3/1b4pp/3r2k1/40 White to move 8 - R - B K * - R 7 * - r - * P P P 6 P * - * P * - * 5 * B * - p - * Q 4 - * - * q p - * 3 * - * - n - * - 2 - b - * - * p p 1 * - * r * - k - a b c d e f g h Source: unknown. This one we left the machine ran overnight. It found that 1. Rd8! wins. 1. Rd8! Kd8 2. Ra7 and if 2. ... Qe2 3. Qd4 Ke8 4. h3... Took 12 hours to get the value back, but would have played it if the time control is 6 hours/move. 8 ;r3;r;b;k1/;p;p;q2;p;p;p/2;b1;pb2/8/6q1/1p1b3p/p1p2pp1/r2r2k1/40 White to move 8 R * - * R B K * 7 P P Q - * P P P 6 - * B * P b - * 5 * - * - * - * - 4 - * - * - * q * 3 * p * b * - * p 2 p * p * - p p * 1 r - * r * - k - a b c d e f g h Source: Gufeld-Osnos, USSR 1978. The move played was 1. Bh7, but as it turns out 1. Bh7 might not be the best move. Osnos defended poorly and got slaughtered. With best black defence, white only maintains a positional edge after 1. Bh7 Kh7 2. Qh5 Kg8 3. Rd4 Bf3! (with the idea of Qxc2, and then Q to king side to defend the king). DT-2 prefers to play c4, which threatens Bh7 for real. 9 ;r4;r1;k/4;b;p;p;b/2;n1;p2;p/;p1;n1p3/1;p1;p1bnp/3p1np1/;qp2qpb1/2rr2k1/40 White to move 8 R * - * - R - K 7 * - * - B P P B 6 - * N * P * - P 5 P - N - p - * - 4 - P - P - b n p 3 * - * p * n p - 2 Q p - * q p b * 1 * - r r * - k - a b c d e f g h Source: unknown. After 9 minutes, it played 1. Nf6, expecting 1. ... Rfc8 2. Nh7 Kh7 3. Ra1 ... The score was slightly nagative for white. On longer searches, it went up to half a pawn and creeping up. 10 ;r1;b2;r;k1/1;p1;n;b;p;p;p/;p;q1;p4/3b4/p2np3/2n1;p3/1pp3pp/r2q1r1k/40 White to move 8 R * B * - R K * 7 * P * N B P P P 6 P Q - P - * - * 5 * - * b * - * - 4 p * - n p * - * 3 * - n - P - * - 2 - p p * - * p p 1 r - * q * r * k a b c d e f g h Source: Van der Wiel-Ribli, Amsterdam 1980. Solution is 1. Rf7 Rf7 2. Bf7 Kf7 3. Qh5. Plays it in less than 2 minutes, score stablized within 5 minutes to a pawn plus. 11 ;r1;b3;k1/;p2;p1;np1/2;p;q;r1r;p/1;p2;p2p/2b1p;nq1/1p6/p1pp4/1k4r1/40 White to move 8 R * B * - * K * 7 P - * P * N p - 6 - * P Q R * r P 5 * P * - P - * p 4 - * b * p N q * 3 * p * - * - * - 2 p * p p - * - * 1 * k * - * - r - a b c d e f g h Source: unknown Be6 appears somewhat worse for white, but 1. Rh6 Nh6 2. Qg5 Nf7 3. Qd8 appears to be a repetition draw or slightly ahead for white. Plays 1. Rh6 after 5 minutes, thought white was slightly ahead, but going down the line, it appeared that black had enough pressure for a draw.
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