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Subject: Re: One easy mate to solve (white K missing) Correction!!!

Author: leonid

Date: 04:19:29 07/26/01

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On July 25, 2001 at 22:39:52, Heiner Marxen wrote:

>On July 25, 2001 at 15:12:21, leonid wrote:
>
>>On July 25, 2001 at 14:02:16, Heiner Marxen wrote:
>>
>>>On July 25, 2001 at 11:12:54, leonid wrote:
>>>
>>>>Hi!
>>>>
>>>>If you are in the mood to solve one mate, try this:
>>>>
>>>>[D]kr1rBR2/bn1qQbN1/q2QqQ2/2nqQqB1/3QqQ2/3qQqN1/3QqQ2/4R1K1 w - -
>>>>
>>>>Please indicate your result.
>>>>
>>>>Thanks,
>>>>Leonid.
>>>
>>>Hi Loenid,
>>>
>>>One of the 10 white queens surely is meant to be a king, but which one?
>>>
>>>Cheers,
>>>Heiner
>>
>>Thanks, Heiner for indicate my mistake! This time will try to look  well into
>>position after  its deposition.
>>
>>Cheers,
>>Leonid.
>
>Hi again,
>
>Chest says this is a mate in 12, so it is not exactly easy for Chest.
>But since black has considerably counter measures, the effective branching
>factor is quite moderate.  Chest needs 5 hours to complete its analysis:
>
>PV: Qxb8+ Rxb8 Qxb8+ Bxb8 Qxb8+ Kxb8 Bxd7+ Be8 Rxe8+ Ka7 Qexc5+ Qxc5 Qxc5+ Qxc5
>Qxc5+ Nxc5 Qxc5+ Qab6 Qa5+ Qa6 Qcxb6+ Qxb6+ Qfxb6#
>
> depth   time    EBF[T]              EBF[N]
>#  1      0.00s                 0kN           0.87          1-         0
>#  2      0.00s                 0kN           1.00          1-         0
>#  3      0.01s                 0kN [  6.20]  0.93         80-         0
>#  4      0.07s [  7.00]        2kN [  4.57]  1.07        339-         0
>#  5      0.24s [  3.43]        9kN [  4.04]  1.31       1341-         0
>#  6      1.19s [  4.96]       45kN [  4.85]  1.57       6240-         0
>#  7      4.34s [  3.65]      171kN [  3.84]  1.88      24208-         0
>#  8     18.54s [  4.27]      753kN [  4.41]  2.25     108884-         0
>#  9     88.51s [  4.77]     3772kN [  5.01]  2.63     538579-         0
># 10    427.96s [  4.84]    18772kN [  4.98]  3.14    2625882-       312
># 11   2131.48s [  4.98]    94378kN [  5.03]  3.63   12931582-   4264574
># 12  17041.89s [  8.00]   799505kN [  8.47]  3.38  103238047-  94490146
>
>Cheers,
>Heiner

Hi, Heiner!

It is mainly because of very nice general conditions for solving it by selective
search that I named it as "easy". Selective took slightly less that one second
(0.82 sec).

Probably our brute force is very close and difference is mainly in the use of
hash. If you would to glance over my search it is here:

Moves       Time        Branching factor.
4           0.055 sec
                        6
5           0.329 sec
                        4.33
6           1.428 sec
                        4.65
7           6.648 sec
                        5.066
8           28.18 sec
                        5.2
9           148 sec
                        6.3
10          15 min 38 sec
                        10.33
11          2 hour 41 min 29 sec


12 - first mate found in 2 min 31 sec.

Cheers,
Leonid.



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