Author: Uri Blass
Date: 15:47:39 09/17/05
Go up one level in this thread
On September 17, 2005 at 18:03:16, Dieter Buerssner wrote:
>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.
Fruit is using history based pruning when after fail high it does research with
the original depth.
I believe that it is possible that history based pruning is responsible here.
It may be interesting to see output of Fruit WCCC without history based pruning.
I thought that part of the difference between Fruit and Yace may be because of
better evaluation of Fruit of king safety but inspite of the fact that I
consider yace as worse in king safety evaluation it seems not to be the case in
this position based on scores at small depths.
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
I have no Fruit WCCC but here is Fruit2.1's analysis and it also has a jump in
score unlike yace.
New game,
[D]1r1b1rk1/1qp2pnp/2bp3Q/2p2N2/p3P1P1/P4P2/1PP4P/2KN2RR b - - 0 1
Analysis by Fruit 2.1:
2...Nxf5 3.gxf5+ Bg5+ 4.Rxg5+ Kh8
± (1.39) Depth: 1/5 00:00:00
2...Ne6
-+ (-1.78) Depth: 1/8 00:00:00
2...Ne6 3.g5
-+ (-1.55) Depth: 2/9 00:00:00
2...Ne6 3.g5 Qa6
-+ (-1.80) Depth: 3/9 00:00:00
2...Ne6 3.g5 Kh8 4.h4
-+ (-1.62) Depth: 4/10 00:00:00
2...Ne6 3.g5 Kh8 4.h4 Qa6
-+ (-1.87) Depth: 5/15 00:00:00
2...Ne6 3.g5 d5 4.Rg4 dxe4 5.f4
-+ (-2.52) Depth: 6/18 00:00:00 54kN
2...Ne6 3.g5 Kh8 4.h4 c4 5.h5 Qa7
-+ (-1.84) Depth: 7/27 00:00:00 121kN
2...Ne6 3.g5 Kh8 4.Rg4 Rg8 5.Rhg1 Rg6 6.Qh5
-+ (-1.83) Depth: 8/27 00:00:00 243kN
2...Ne6 3.g5 Kh8 4.h4 Qa6 5.Rh2 Rg8 6.Qh5 Rg6
-+ (-1.93) Depth: 9/32 00:00:01 511kN
2...Ne6 3.g5 Be8 4.Rg3 Qc8 5.Nde3 Qd7 6.Nd5 Qb5 7.Nf6+ Bxf6 8.Qxf6
µ (-0.77) Depth: 10/33 00:00:02 1611kN
2...Ne6 3.g5 Be8 4.Rg3 Qc8 5.Nde3 Qd7 6.Nd5 Kh8 7.Nf6 Bxf6 8.Qxf6+ Kg8
³ (-0.67) Depth: 11/37 00:00:03 2754kN
2...Ne6 3.g5 Bxe4 4.fxe4 Qxe4 5.g6 fxg6 6.Rxg6+ Kh8 7.Rxe6 Qxf5 8.Rg1 Bf6 9.Re7
Bd4
µ (-0.75) Depth: 12/40 00:00:11 9151kN
2...Ne6 3.g5 Bxe4 4.g6 fxg6 5.Rxg6+ Kh8 6.Rxe6 Bg5+ 7.Qxg5 Bxf5 8.Rg1 Rf7 9.Qe3
Bg6 10.Re8+ Rf8 11.Rxb8 Rxb8
³ (-0.26) Depth: 13/44 00:00:21 17574kN
2...Ne6 3.g5 Bxe4 4.g6 fxg6 5.Rxg6+ Kh8 6.Rxe6 Bg5+ 7.Qxg5 Bxf5 8.Rg1 Rf7 9.Qe3
Qd5 10.Qc3+ Qd4 11.Qxd4+ cxd4
= (0.01) Depth: 14/52 00:00:52 43398kN
2...Ne6 3.g5 Bxe4 4.g6 fxg6 5.Rxg6+ Kh8 6.Rhg1 Bg5+ 7.R1xg5 Bxf5 8.Rxe6 c6 9.Rf6
Qe7 10.Rfxf5 Rxf5 11.Rxf5
+- (2.77) Depth: 15/58 00:07:21 365277kN
(, 18.09.2005)
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