Author: GeoffW
Date: 10:57:20 08/25/04
Go up one level in this thread
On August 25, 2004 at 12:52:46, Volker Böhm wrote:
>
>Hi,
>
>the following position of the iq - test (position 166) cannot be solved from
>spike in reasonalbe time (> 2h):
>
>r4r1k/6pp/3p3b/1p1Npb2/3nB2q/2N3P1/PP3P1P/R2Q1RK1 b - - 0 1
>
>(The move to find is Qxe4)
>
>The reason is a nullmove-problem. After the queen-sac there are many moves that
>leads to a mate-thread. But one queen back spike tends to prune because of
>nullmove result.
>
>I tested the position with fritz 8, he solves it in 8 ply in nearly no time.
>(PRODEO NEEDS 7 Ply, Ruffian 1.01 11 Ply).
>
>Are there non commercial engines that solves this position too in a short amount
>of time?
>Maybe the author of this engine would be so kind to explain the rule that solves
>the nullmove-problem.
>
>Thanks Volker
Hello Volker
I tried it with my program, like yours it couldnt get the correct move even
after a long search. I also disabled my null moving and still it was equally
clueless, so doesn't appear to be a null move issue ?
I did manage to solve it in ten seconds however by tweaking my Queen value down
from 975 to 900. This then gave the output below.
What is your Queen value ?
Regards Geoff
FEN: r4r1k/6pp/3p3b/1p1Npb2/3nB2q/2N3P1/PP3P1P/R2Q1RK1 b - - 0 1
1 00:00 433 433 +0.02 Qh3 Bxf5 Rxf5
2 00:00 886 886 +0.02 Qh3
3 00:00 8.848 884.800 -0.08 Qg4 Bxf5 Qxf5
4 00:00 16.325 1.632.500 -0.14 Qg4 Bxf5 Qxf5 f4
5 00:00 68.848 983.542 -0.14 Qg4 f3 Qh3 Nf4 Bxf4 Bxa8 Bxg3 hxg3 Rxa8
6 00:00 165.457 919.205 -0.19 Qg4 Bxf5 Qxf5 f4 Rad8 Rc1
7 00:01 819.461 910.512 -0.02 Qh3
8 00:02 2.241.365 903.776 -0.11 Qh3 f4 Bxe4 Nxe4 Rfd8 Qd3 Ra4 fxe5 dxe5
9 00:10 9.267.108 882.581 +0.31 Qxe4 Nxe4 Bxe4 Nc3 Bf3 Qd3 b4 Rfe1 bxc3
bxc3 Ra3
10 00:18 16.383.527 885.596 +0.21 Qxe4 Nxe4 Bxe4 Nc3 Bf3 Qd3 b4 Rfe1 bxc3
bxc3 Ra3 Reb1
11 00:34 31.049.334 913.215 +0.44 Qxe4 Nxe4 Bxe4 Nc3 Bf3 Qd3 b4 Rfe1 bxc3
bxc3 Ra3 h4 Rb8
12 01:25 74.898.518 881.159 +0.82 Qxe4 Nxe4 Bxe4 Nc3 Bf3 Qd3 b4 Rae1 bxc3
bxc3 Ra3 Qc4 d5 Qc5
13 06:30 339.121.825 869.543 +0.61 Qxe4 Nxe4 Bxe4 Nc3 Bf3 Qd3 b4 Rae1 bxc3
bxc3 Ra3 Qc4 Nc2 Rb1 Bd2
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