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Subject: Re: difficult defence (testposition)

Author: John Merlino

Date: 11:28:23 12/29/02

Go up one level in this thread


On December 29, 2002 at 10:34:56, Thomas Lagershausen wrote:

>[D]r2qr1k1/1p3p1p/p1b1pbpB/4N3/Pn1P4/6R1/1P2QPPP/1B1R2K1 b - - am Bxa4
>
>In a game Spasski-Pachman (Manila 1976) Pachman found the good defence Nb4-d5-e7
>to bring a further defender to his king to protect the weak g6 square.
>
>Wrong is of course ...Bxa4 ?? after b3 nebst Qh5 and Lxg6 white´s attack is
>decisive.Maybe an immediate is also decisive.
>
>Here are an example that this tasc of defence is not trivial.
>
>Two strong programs on paralell analysis on Athlon 1,5 Ghz under Arena-GUI:
>
>s: Yace 0.99.68  UCI 100 MB:
>T1  00:00  -0,97   Lxe5 dxe5
>T1  00:00  0,46   Lxa4
>T2  00:00  0,45   Lxa4 b3
>T3  00:00  0,58   Lxa4 b3 Lc6 Sxc6 Sxc6
>T4  00:00  0,47   Lxa4 b3 Lc6 Tc3
>T5  00:00  0,68   Lxa4 b3 Lb5 Dg4 Dd5
>T6  00:00  0,60   Lxa4 b3 Lc6 Dg4 Dd5 Tc1
>T7  00:01  0,62   Lxa4 b3 Lc6 Dg4 Dd6 Sxc6 Sxc6
>T8  00:04  0,60   Lxa4 b3 Lc6 Dh5 De7 Tc1 Tac8 Dg4
>T9  00:15  0,62   Lxa4 b3 Lc6 Dg4 Dd6 Sxc6 Sxc6 Le4 Tad8 d5
>T10  02:16  0,48   Lxa4 b3 Lc6 Dh5 Te7 Sxf7 Txf7 Lxg6 hxg6 Dxg6 Lg7 Lxg7 Dd5
>T11  04:54  0,51   Lxa4 b3 Lc6 Dh5 Dc7 Sxg6 fxg6 Lxg6 Te7 Lxh7 Kh8 Lg6 Tc8
>T12-  05:39  0,11   Lxa4 b3 Lc6 Dh5 Dc7 Lxg6 fxg6 Sxg6 Lg7 Lxg7 Dxg3 hxg3 hxg6
>T12  01:09:23  -0,14   Lxa4 b3 Lc6 Dh5 Te7 Sxf7 Txf7 Lxg6 Tc7 Lxh7 Kh8 Tg8 Dxg8
>Lxg8 Txg8 Lg5 Kg7
>T13-  01:11:03  -0,54   Lxa4 b3 Lc6 Dh5 Te7 Sxf7 Txf7 Lxg6 Tc7 Lxh7 Kh8 Tg8 Dxg8
>Lxg8 Tac8 Lg5 Kg7
>T13  01:18:54  -0,88   Lxa4 b3 Lc6 Dh5 Dc7 Lxg6 fxg6 Sxg6 hxg6 Txg6 Lg7 Txg7
>Dxg7 Lxg7 Kxg7 De5 Kh6 Te1
>T13+  01:28:30  -0,87   Dd5 Dh5 Te7 Sg4 Lxd4 Sf6 Lxf6 Txd5 exd5 Txg6 hxg6 Lxg6
>T13  02:00:00  -0,16   Dd5 Dh5 Te7 b3 Tc7 Sg4 Le7 De5 Dxe5 dxe5 Tac8 Sf6 Lxf6
>exf6 Sd5
>
>Aristarch 4.4  UCI 86 MB:
>T2  00:00  0,21   Lxa4 b3
>T3  00:00  0,36   Lxa4 b3 Lb5
>T4  00:00  0,25   Lxa4 b3 Lb5 Dg4
>T5  00:00  0,53   Lxa4 b3 Lb5 Dg4 Tc8
>T6  00:00  0,31   Lxa4 b3 Lc6 Dg4 Tc8 Tc1
>T7  00:00  0,37   Lxa4 b3 Lb5 Dg4 Lh4 Th3 g5
>T8  00:01  0,30   Lxa4 b3 Lc6 Dg4 Ld5 h3 Tc8 Te1
>T9  00:04  0,47   Lxa4 b3 Lb5 Dg4 Sc6 Lc2 Tc8 Le4 Sxd4
>T10  00:08  0,45   Lxa4 b3 Lb5 Dh5 De7 Dg4 Sc6 Df4 Tad8 Lc2
>T11  00:31  0,47   Lxa4 b3 Lb5 Dh5 Dc7 Le4 Tad8 Lf4 Lg7 Dg4 Tc8
>T12  02:50  0,50   Lxa4 b3 Lc6
>T13  10:46  0,37   Lxa4 b3
>T14  26:40  0,07   Lxa4 b3 Lb5 Dh5
>T15  01:29:04  -0,13   Lxa4 b3 Lc6
>
>So no result by Aristarch and a subperfect solution by Yace.
>
>What is the opinion of your favorite program?
>
>TL

Chessmaster 9000, on a humble P3-733, still has not found Nd5 after almost 90
minutes.

However, in just over 2 minutes it found that Bxa4 was better for White (0.08),
which appears at least to be better than the above two programs. In just under
10 minutes it found that it was even better for White (0.73), and there was a
huge fail-low which did not resolve after over 75 minutes!

Time	Depth	Score	Positions	Moves
0:00	1/3	0.05	1251		1...Bxa4 2.b3 Bb5 3.Qd2
0:00	1/4	-0.64	4762		1...Bxa4 2.b3 Bb5 3.Qd2 Nd5
0:00	1/5	-0.47	24503		1...Bxa4 2.b3 Bb5 3.Qd2 Nd5 4.Rc1
0:01	1/6	-0.69	63668		1...Bxa4 2.b3 Bb5 3.Qd2 Nd5 4.Rc1
					Qd6
0:03	1/7	-0.69	140442		1...Bxa4 2.b3 Bb5 3.Qd2 Nd5 4.Rc1
					Qd6
0:06	1/8	-0.26	372786		1...Bxa4 2.b3 Bb5 3.Qh5 Qc7 4.Rc1
					Qe7 5.Bg5 Nd5 6.Bxf6 Qxf6
0:15	1/9	-0.26	1111867		1...Bxa4 2.b3 Bb5 3.Qh5 Qc7 4.Rc1
					Qe7 5.Bg5 Nd5 6.Bxf6 Qxf6
0:52	1/10	-0.09	4194171		1...Bxa4 2.b3 Bc6 3.Qh5 Qc7 4.Nxg6
					fxg6 5.Bxg6 Kh8 6.Bxe8 Rxe8 7.Qg4
2:19	2/11	0.08	11512758	1...Bxa4 2.b3 Bc6 3.Qg4 Qc7 4.Nxg6
					fxg6 5.Bxg6 Kh8 6.Bxe8 Rxe8 7.Bf4
					Qg7 8.Qe2
9:54	3/12	0.73	50565289	1...Bxa4 2.Bxg6 fxg6 3.Nxg6 Qc7
					4.b3 Bxb3 5.Ne5+ Kh8 6.Rxb3 Bxe5
					7.dxe5 Nd5 8.Rg3
1:25:23	3/12	0.52	334614650	1...Qc7 2.Bf4 Qd8 3.Qd2 Nd5 4.Nxc6
					bxc6 5.Be5 Bxe5 6.dxe5 Qh4 7.Qc2
					Qh5 8.Re1

jm



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