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Subject: Re: mate threat extension/null move

Author: Stuart Cracraft

Date: 19:35:37 09/25/04

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On September 25, 2004 at 17:19:04, Andrew Platt wrote:

>On September 25, 2004 at 16:35:05, Stuart Cracraft wrote:
>
>>So do you solve WAC 141 in a reasonable amount of time?
>
>As I said, I don't see the mate score in a reasonable time but I do find Qxf4!:
>
> 6   -178         6      45906 Kf1 b4 Bc4 Nd5 Bg5 f5
> 6   -178         6      47494 Kf1 b4 Bc4 Nd5 Bg5 f5
> 7   -172        26     191354 Kf1 a5 Bg5 Nd3 Qc2 Re1+ Kg2 Re8
> 7   -172        28     201701 Kf1 a5 Bg5 Nd3 Qc2 Re1+ Kg2 Re8
> 8   -163        89     666343 Kf1 a5 Bg5 Ne6 Bxe6 Rxe6 Kg1 f5
> 8   -163        92     692725 Kf1 a5 Bg5 Ne6 Bxe6 Rxe6 Kg1 f5
> 9   -124       823    6360825 Kf1 Rc8 Qb1 Nd5 Kg1 b4 Bg5 Be7 f4
> 9   +137      1218    9592419 Qxf4 ++
> 9   +764      1459   11570166 Qxf4 Bxf4 Rxh5 gxh5 Rxh5 Bh6 Rxh6 Qg3+ fxg3 Re2+
>Kh3 Rh2+ Kxh2 a5
> 9   +764      1462   11596859 Qxf4 Bxf4 Rxh5 gxh5 Rxh5 Bh6 Rxh6 Qg3+ fxg3 Re2+
>Kh3 Rh2+ Kxh2 a5
>10   +764      1834   14726581 Qxf4 Bxf4 Rxh5 gxh5
>10   +764      1870   15025646 Qxf4 Bxf4 Rxh5 gxh5
>
>As you can see it misses the mate near the bottom. It extends at Rxh5 (mate
>threat), Rxh5 again, Rxh6 (mate threat still), Qg3+ (check). I forget exactly
>why it misses the mate at the bottom. I know it drops into qsearch with Rh8#
>being move it doesn't consider because it's a capture; I think the line it comes
>up with happens because it has the most extensions and captures!
>
>I don't consider this conclusive; I expect I could change the search for
>something else and find this one disappears again!
>
>Andy.

My program won't solve it without recapture extention enabled. And
then only in about 2-3 minutes on a 1ghz P3. With the best settings
for WAC overall, which doesn't include that extension, WAC 141
completely befuddles the program.

Wish I could get this one solved. David -- how does GES do on WAC 141?

Am willing to publish my search()+quiesce() code verbatim to get input
from anyone who really has a handle on 141 and wants to help.

Alpha=-1332 Beta=-531 Maxdepth=9999999 MaxTime=9999999
 1/ 9  g2f1  0.00 -953      352 g2f1 f4d5
                                g2f1 f4d5
 2/ 9  g2f1  0.01 -953      730
                                g2f1 f4d5 c1g5
 3/11  g2f1  0.02 -953     2018
                                g2f1 f4d5 c1g5 d5f6
 4/14  g2f1  0.07 -953    10025
                                g2f1 f4d5 b3d5 c6d5 f1g2
 5/17  g2f1  0.43 -953    77695
                                g2f1 b5b4 b3a4 f4d5 f6g5 d5e7
 6/23  g2f1  1.57 -953   225860
                                g2f1 b5b4 b3a4 f4d5 f6g5 d5e7
 7/28  g2f1  8.76 -939  1778751 g2f1 a7a5 f6g5 f4e6 c1e3 d6e7 g5e7 d7e7
                                g2f1 a7a5 f6g5 f4e6 c1e3 d6e7 g5e7 d7e7
 8/29  g2f1 17.28 -939  3143034
                                g2f1 a7a5 f6g5 f4e6 h4e4 a5a4 b3e6 e8e6 f1g1
 9/34  g2f1 27.41 -939  4951637
                                g2f1 a7a5 f6g5 f4e6 h4e4 a5a4 b3e6 e8e6 f1g1
10/41  g2f1 71.45 -939 12724480
                                g2f1 a7a5 f6g5 f4e6 h4e4 a5a4 b3e6 e8e6 f1g1
                                e6e4



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