Author: Dieter Buerssner
Date: 15:03:16 09/17/05
Go up one level in this thread
On September 16, 2005 at 06:29:42, Thomas Lagershausen wrote:
>[D]1r1bnrk1/1qp2ppp/2bp3B/2p2N2/p3P1P1/P4P2/1PPQ3P/2KN2RR w - - 11 20
>
>20.Bxg7 !! wins in all variations.
>
>Any programs of today are able to solve this?
Some maybe interesting observation for this position, I just discussed with
Stefan Knappe ("Matador", he brought my attention to this) . Both Shredder and
Fruit WCC did solve it in a similar manner. They both needed some time, and then
solved it. They both got a rather huge fail high directly (to 6.x and to 3.x,
respectively). At the time we discussed this, I just had forced the moves Bxg7
Nxg7 Qh6 in Yace, and after the first fail low, the score went up down
continuesly (from black's point of view). I wonder, how jumps in score of Fruit
and Shredder can be explained? Is it a typical selective search issue? I cannot
imagine, that null move is the reason here, however, in other cases I could
imagine such a score jump be caused by null move. Some move will be seemingly
refuted by a null move (possibly deeper down in the variation) at a much reduced
search depth. At some point, the null move will not be able to refute, and now a
real search starts. Now we search this line a couple of plies deeper
immediately, which could cause a much deeper "understanding" of the position,
and such a score jump. What technique are Fruit and Shredder using, that may
explain the score jump here?
It might be interesting to see analysis different engines for the root position
(possibly with lots of patience) compared to the analysis after Bxg7 Nxg7, and
after Bxg7 Nxg7 Qh7. Do Shredder and Fruit show similar huge score jumps now?
Yace is rather predictable here. Afte Qh6, it shows very small advantage for
white at depth 12, somewhat larger advantage at depth 13. With the recapture at
the start of the line, one could guess, that at depth 14 (when no other move
shows positive score) or at depth 15 in the root position the move will be
found. Exactly that happened. Analysis further down.
Regards,
Dieter
From the root position:
1r1bnrk1/1qp2ppp/2bp3B/2p2N2/p3P1P1/P4P2/1PPQ3P/2KN2RR w - -
Engine: Yace via ssh (700 MB)
von Dieter Buerssner
14/44 5:20 +0.08 1.Lg5 f6 2.Le3 Tf7 3.Te1 Td7 4.h4 Db5
5.De2 Dxe2 6.Txe2 Lb5 7.Td2 g6 8.Sg3 (288.780.070) 902
14/46 7:58 +0.08 1.Lg5 f6 2.Le3 Tf7 3.Te1 Td7 4.h4 Db5
5.De2 Dxe2 6.Txe2 Lb5 7.Td2 g6 8.Sg3 (456.342.873) 954
15/46 13:34 +0.07 1.Lg5 Lxg5 2.Dxg5 f6 3.Dh4 Ld7
4.Se7+ Kf7 5.Sd5 Kg8 6.g5 Tf7 7.gxf6 Sxf6
8.Sxf6+ Txf6 (742.157.917) 911
15/55 36:30 +0.08++ 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Le8 4.Tg3 Kh8
5.Thg1 c6 6.Sxd6 Lxg5+ 7.Txg5 Td8
8.Sxb7 Sxg5 (2.124.011.250) 969
15/55 39:41 +0.48++ 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Le8 4.Tg3 Kh8
5.Thg1 c6 6.Th3 f6 7.g6 Dg7 8.Sxg7 Sxg7 (2.299.314.625)
965
15/55 39:45 +0.48 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Le8 4.Tg3 (2.304.130.942) 965
15/55 40:35 +0.48 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Le8 4.Tg3 (2.349.987.716) 964
16/55 44:50 +0.88++ 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Le8 4.Tg3 Kh8
5.Thg1 c6 6.Th3 f6 7.g6 Lxg6 8.Txg6 Dg7
9.Txg7 Sxg7 (2.591.912.344) 963
16/55 50:48 +1.36 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Lxe4 4.g6 fxg6
5.Txg6+ Kh8 6.Txe6 Lg5+ 7.Dxg5 Txf5
8.Dg4 Lxc2 9.Te7 Tg8 10.Dh4 Tg7
11.Kxc2 (2.922.985.737) 958
16/55 55:47 +1.36 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Lxe4 4.g6 fxg6
5.Txg6+ Kh8 6.Txe6 Lg5+ 7.Dxg5 Txf5
8.Dg4 Lxc2 9.Te7 Tg8 10.Dh4 Tg7
11.Kxc2 (3.208.273.117) 958
17/57 70:00 +1.76++ 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Lxe4 4.g6 fxg6
5.Txg6+ Kh8 6.Txe6 Lg5+ 7.Dxg5 Txf5
8.Dg4 Lxc2 9.Tg1 c6 10.Kxc2 Db3+
11.Kb1 Dd3+ 12.Ka2 Te8 13.Txe8+ Tf8 (4.022.260.535) 957
17/60 99:16 +2.76++ 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Lxe4 4.g6 fxg6
5.Txg6+ Kh8 6.Txe6 Lg5+ 7.Dxg5 Txf5
8.Dh6 Txf3 9.Te1 Ld5 10.Te8+ Lg8
11.Txg8+ Txg8 12.Te7 Db3 13.cxb3 Txb3 (1.384.992.478) 232
17/60 127:12 +3.14 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Lxe4 4.g6 fxg6
5.Txg6+ Kh8 6.Txe6 Lg5+ 7.Dxg5 Txf5
8.Dh6 Txf3 9.Te1 Txa3 10.Df6+ Kg8
11.Tg1+ Lg6 12.Txg6+ hxg6 13.Dxg6+ Kh8
14.Dh6+ (2.935.261.196) 384
17/60 136:35 +3.14 1.Lxg7 Sxg7 2.Dh6 Se6 3.g5 Lxe4 4.g6 fxg6
5.Txg6+ Kh8 6.Txe6 Lg5+ 7.Dxg5 Txf5
8.Dh6 Txf3 9.Te1 Txa3 10.Df6+ Kg8
11.Tg1+ Lg6 12.Txg6+ hxg6 13.Dxg6+ Kh8
14.Dh6+ (3.467.742.425) 423
And after Bxg7 Nxg7 Qh6; score from black's point of view; hash tables cleared:
1r1b1rk1/1qp2pnp/2bp3Q/2p2N2/p3P1P1/P4P2/1PP4P/2KN2RR b - -
11/34 0:13 +1.35 2...Se6 3.g5 Te8 4.Dh5 Te7 5.Sxe7+ Lxe7
6.Tg4 Db5 7.Dh6 c4 8.Thg1 c3 (14.228.009) 1041
12/37 0:21 +0.95-- 2...Se6 3.g5 Te8 4.g6 hxg6 5.Txg6+ fxg6
6.Dxg6+ Kf8 7.Tg1 Lg5+ 8.Txg5 Lxe4
9.fxe4 Sg7 (22.512.204) 1045
12/37 0:32 -0.05-- 2...Se6 3.g5 Te8 4.g6 hxg6 5.Txg6+ fxg6
6.Dxg6+ Kf8 7.Tg1 Lg5+ 8.Txg5 Db4
9.axb4 Sxg5 (33.433.627) 1040
12/37 0:33 -0.05 2...Se6 3.g5 Le8 4.Dg7+ Sxg7 5.Sxg7 (34.972.433) 1044
12/38 0:39 -0.05 2...Se6 3.g5 Le8 4.Dg7+ Sxg7 5.Sxg7 (41.215.380) 1032
13/40 0:57 -0.45-- 2...Se6 3.g5 Le8 4.Tg4 Kh8 5.Thg1 Lxg5+
6.Txg5 Db3 (60.809.596) 1060
13/40 1:15 -0.57 2...Se6 3.g5 Lxe4 4.g6 fxg6 5.Txg6+ Kh8
6.Txe6 Lg5+ 7.Dxg5 Txf5 8.Dh6 Txf3
9.Te7 Tg8 10.Te1 d5 11.T1xe4 Tg6
12.Txh7+ Kg8 (80.836.344) 1076
13/41 1:26 -0.57 2...Se6 3.g5 Lxe4 4.g6 fxg6 5.Txg6+ Kh8
6.Txe6 Lg5+ 7.Dxg5 Txf5 8.Dh6 Txf3
9.Te7 Tg8 10.Te1 d5 11.T1xe4 Tg6
12.Txh7+ Kg8 (92.184.397) 1069
14/47 2:04 -0.97-- 2...Se6 3.g5 Lxe4 4.g6 fxg6 5.Txg6+ Kh8
6.Txe6 Lg5+ 7.Dxg5 Txf5 8.Dg4 Te5
9.fxe4 Dc8 10.Tg1 Txe4 (133.076.466) 1073
14/47 2:46 -1.36 2...Se6 3.g5 Lxe4 4.g6 fxg6 5.Txg6+ Kh8
6.Txe6 Lg5+ 7.Dxg5 Txf5 8.Dg4 Lxc2
9.Te7 Tg8 10.Dh4 Tg7 11.Kxc2 Txe7
12.Dxe7 (179.467.154) 1081
14/47 3:06 -1.36 2...Se6 3.g5 Lxe4 4.g6 fxg6 5.Txg6+ Kh8
6.Txe6 Lg5+ 7.Dxg5 Txf5 8.Dg4 Lxc2
9.Te7 Tg8 10.Dh4 Tg7 11.Kxc2 Txe7
12.Dxe7 (200.601.272) 1077
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