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Subject: Re: Larsen - Kavalek 1979

Author: Mike Byrne

Date: 06:55:27 09/07/03

Go up one level in this thread


On September 06, 2003 at 21:58:14, Kim Roper Jensen wrote:

>Position from the game Larsen - Kavalek Montreal Tournament of Stars
>
>[D]1k6/8/B3K1P1/5P2/1pRr2Nn/2b5/8/8 b - -
>
>Only move here for black is Nxf5 and get both white pawns and it should be a
>draw - according to the notes by Whiteley (its taken from the tournament book,
>by Tal, Chepizhny & Roshal)
>
>Shredder 6 Paderborn Classical finds Nxf5 fast, but no drawscore after a long
>time ... this on 2Ghz AMD with 256MB hashtable but very limited
>endgametablebases
>
>Anyone sees this with a draw score ?
> or have a large collection of endgametablebases :)
>
>  1.00	 0:00 	-7.08--	1...Rxg4 2.Rxg4 (2)
>  1.00	 0:00 	-7.29 	1...Rxg4 2.Rxg4 (4)
>  1.00	 0:00 	-7.04++	1...Rxc4 2.Bxc4 (5)
>  1.00	 0:00 	-6.11++	1...Rxc4 2.Bxc4 (7)
>  1.00	 0:00 	-3.47 	1...Rxc4 2.Bxc4 (9)
>  1.00	 0:00 	-2.30++	1...Rd8 (21)
>  1.00	 0:00 	-2.30 	1...Rd8 (22)
>  2.00	 0:00 	-2.55--	1...Rd8 2.Rf4 (47)
>  2.00	 0:00 	-3.09--	1...Rd8 2.Nf6 Bxf6 3.Kxf6 (65)
>  2.00	 0:00 	-3.19 	1...Rd8 2.Nf6 Bxf6 3.Kxf6 (91) 9.1
>  2.00	 0:00 	-3.15++	1...Rxc4 2.Bxc4 Bg7 (122) 12.2
>  2.00	 0:00 	-3.15 	1...Rxc4 2.Bxc4 Bg7 (144) 14.4
>  3.00	 0:00 	-3.43--	1...Rxc4 2.Bxc4 Kb7 3.Nf6 (389) 38.9
>  3.00	 0:00 	-3.96--	1...Rxc4 2.Bxc4 Bd4 3.Nf6 (455) 45.5
>  3.00	 0:00 	-4.21 	1...Rxc4 2.Bxc4 Bg7 3.f6 Nxg6 4.fxg7 (573) 57.3
>  3.00	 0:00 	-4.16++	1...Rd8 2.Bb5 Bg7 (768) 76.8
>  3.00	 0:00 	-3.81++	1...Rd8 2.Nf2 Re8+ 3.Kf7 (851) 85.1
>  3.00	 0:00 	-3.41 	1...Rd8 2.Nf6 Nf3 (1.030) 103.0
>  3.00	 0:00 	-3.35++	1...Ka7 2.Rxd4 Bxd4 3.Bb7 (1.786) 178.6
>  3.00	 0:00 	-3.35 	1...Ka7 2.Rxd4 Bxd4 3.Bd3 (1.814) 90.7
>  4.00	 0:00 	-3.17 	1...Ka7 2.Rxd4 Bxd4 3.Bc4 Bg7 (2.777) 138.8
>  5.00	 0:00 	-3.45--	1...Ka7 2.Rxd4 Kb8 3.Nf6 Bxd4 (4.831) 241.5
>  5.00	 0:00 	-4.08--	1...Ka7 2.Rxd4 Bxd4 3.Bc4 Kb6 4.Ne5 (4.936) 246.8
>  5.00	 0:00 	-4.25 	1...Ka7 2.Rxd4 Bxd4 3.Bc4 Bg7 4.f6 Nxg6 5.fxg7 (7.014)
>233.8
>  5.00	 0:00 	-4.24++	1...Rd8 2.Rc8+ Rxc8 3.f6 (8.519) 283.9
>  5.00	 0:00 	-3.89++	1...Rd8 2.Ne5 Re8+ 3.Kd7 Rxe5 4.Rxc3 (8.976) 299.2
>  5.00	 0:00 	-3.10 	1...Rd8 2.Nf6 Nf3 3.Rf4 Nd4+ 4.Kf7 (13.447) 336.1
>  6.00	 0:00 	-3.35--	1...Rd8 2.Nh6 Nf3 3.f6 Re8+ 4.Kf7 Ne5+ 5.Kxe8 Nxc4
>(32.395) 404.9
>  6.00	 0:00 	-3.65 	1...Rd8 2.Nh6 Ng2 3.Rg4 Ne3 4.Rg1 (36.489) 405.4
>  6.00	 0:00 	-3.64++	1...Rd1 2.Ne5 Re1 3.Ke7 (76.312) 448.8
>  6.00	 0:00 	-3.64 	1...Rd1 2.Ne5 Re1 3.Rc5 Rxe5+ 4.Rxe5 Ka7 5.g7 Kxa6 (76.914)
>452.4
>  7.01	 0:00 	-3.89--	1...Rd1 2.Ne5 Bxe5 3.Kxe5 Re1+ 4.Re4 Nf3+ 5.Kf4 Rxe4+
>6.Kxe4 Ka7 7.Kxf3 (94.217) 471.0
>  7.01	 0:00 	-3.93 	1...Rd1 2.Ne5 Re1 3.Rc5 Nf3 4.g7 Nd4+ 5.Kf7 (128.137) 474.5
>  7.02	 0:00 	-3.92++	1...Rd8 2.Ne5 Re8+ 3.Kf7 Rxe5 4.Rc8+ Ka7 5.g7 (138.085)
>476.1
>  7.02	 0:00 	-3.57++	1...Rd8 2.Ne5 Re8+ 3.Kf7 Rxe5 4.Rxh4 (150.721) 486.1
>  7.02	 0:00 	-3.51 	1...Rd8 2.Nh6 Ng2 3.f6 Rf8 4.Ng4 Ne3 (199.233) 485.9
>  8.01	 0:00 	-3.76--	1...Rd8 2.Nh6 Ng2 3.f6 Rf8 4.g7 Ka7 5.gxf8Q Nf4+ 6.Rxf4
>(245.678) 491.3
>  8.01	 0:00 	-4.07 	1...Rd8 2.Nh6 Ng2 3.f6 Rf8 4.g7 Rxf6+ 5.Kd7 Rg6 6.g8Q+ Rxg8
>7.Nxg8 (311.568) 502.5
>  8.02	 0:00 	-4.06++	1...Rd1 2.Ne5 Re1 3.Rc5 Rg1 4.Be2 (357.657) 510.2
>  8.02	 0:00 	-3.91 	1...Rd1 2.Ne5 Re1 3.Rc5 Rg1 4.Bc4 Bxe5 5.Rb5+ Kc7 6.Kxe5
>(387.763) 509.5
>  9.01	 0:01 	-4.16--	1...Rd1 2.Ne5 Re1 3.Rc5 Bxe5 4.Rxe5 Rd1 5.g7 Rd5 (535.029)
>518.9
>  9.01	 0:01 	-4.54 	1...Rd1 2.Ne5 Re1 3.Rc5 Re3 4.g7 Rg3 5.Nc6+ Ka8 6.f6
>(709.127) 524.5
>  9.02	 0:01 	-4.53++	1...Rd8 2.Nh6 Ng2 3.f6 Rf8 4.Rc8+ Rxc8 5.Ke7 (800.161)
>525.7
>  9.02	 0:01 	-4.18++	1...Rd8 2.Nh6 Ng2 3.f6 Rf8 4.Rc8+ Rxc8 5.Nf5 (839.680)
>527.4
>  9.02	 0:01 	-4.18 	1...Rd8 2.Nf6 Ka7 3.Rxh4 Kxa6 4.g7 Bxf6 5.Kxf6 Ka5 6.Rh8 b3
>7.Rxd8 (992.699) 527.4
>  9.22	 0:02 	-4.15++	1...Nxf5 2.Kxf5 (1.199.702) 532.4
>  9.22	 0:02 	-4.15 	1...Nxf5 2.Kxf5 (1.199.703) 530.1
> 10.01	 0:02 	-4.15 	1...Nxf5 2.Kxf5 (1.199.704) 530.1
> 11.01	 0:04 	-3.90++	1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Ke8 Rg5 6.Nh6
>(2.221.819) 539.8
> 11.01	 0:04 	-3.80 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8 Rg5 6.Kh7
>Ka7 7.Kh6 (2.306.924) 543.3
> 12.01	 0:06 	-3.60 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8 Rg5 6.Kh7
>Ka7 7.Bc8 (3.713.093) 546.9
> 13.01	 0:11 	-3.58 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8 Rg5 6.Kh7
>Ka7 7.Bc8 (6.064.995) 532.6
> 14.01	 0:20 	-3.69 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8 Rg5 6.Kh7
>Ka7 7.Bc8 Kb6 8.Bd7 (11.053.434) 533.2
> 15.01	 0:44 	-3.44++	1...Nxf5 2.Kxf5 Rd5+ 3.Ke6 Rg5 4.Kf7 Rf5+ 5.Kg8 Rg5 6.g7
>(22.955.515) 514.6
> 15.01	 0:53 	-3.10 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke4 Rd6 4.Rc8+ Ka7 5.Bc4 Rxg6 6.Ne3
>Rg7 7.Nd5 Rg4+ 8.Kd3 Rg3+ 9.Ke2 Rg7 10.Rf8 (27.889.315) 518.5
> 16.01	 1:52 	-2.94 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke4 Rd6 4.Bc8 Rxg6 5.Kd3 Rd6+ 6.Kc2
>Rd2+ 7.Kb3 Bg7 8.Bf5 (57.503.138) 510.7
> 17.01	 3:22 	-2.83 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke4 Rd6 4.Rc8+ Ka7 5.Be2 Rxg6 6.Kd3
>Bg7 7.Kc2 b3+ 8.Kb1 Kb6 9.Ne3 Rg1+ 10.Rc1 (103.811.322) 513.6
> 18.01	 6:26 	-2.85 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke4 Rd6 4.Rc8+ Ka7 5.Bb5 Kb7 6.Rc5
>Rxg6 7.Ne3 Kb6 8.Rd5 b3 9.Nc4+ Kb7 (197.104.454) 510.3
> 19.01	13:41 	-2.85 	1...Nxf5 2.Kxf5 Rd5+ 3.Ke4 Rd6 4.Rc8+ Ka7 5.Bb5 Rxg6 6.Ne3
>Kb7 7.Rc5 Bg7 8.Nd5 b3 9.Bd7 Rg3 10.Rb5+ (413.891.384) 503.8
>best move: Nh4xf5 time: 22:32.595 min  n/s: 505.376  CPU 96.8%  nodes:
>683.569.436 TB: 1.256.460

This is a type of position where a drawscore may not be suitable.  A draw score
is often reached when the program reached a point where the programmer has
defined it a draw.  Fro example, bishop and the wrong color rook pawn.  Other
instances may be a the 50 move rule, repetition and "equal" pieces with no
pawns.  I don't see in this instance a program is going to see a "draw" in the
search , thus the drawscore is inappropriate.   The best you're going to do is
find the bext move, Nxf5 which most programs do.



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