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Subject: Re: SEE and pin detection

Author: Vasik Rajlich

Date: 02:58:52 09/01/04

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On August 31, 2004 at 14:33:00, Vincent Lejeune wrote:

>On August 31, 2004 at 09:38:25, Vasik Rajlich wrote:
>
>>On August 31, 2004 at 08:15:42, Kolss wrote:
>>
>>>On August 31, 2004 at 06:52:10, Vasik Rajlich wrote:
>>>
>>>>On August 30, 2004 at 19:44:50, Eugene Nalimov wrote:
>>>>
>>>>>On August 30, 2004 at 14:03:49, Dan Honeycutt wrote:
>>>>>
>>>>>>In spite of Dr. Hyatt's admonishment that this was a loser in Crafty, I'm bent
>>>>>>on trying it.  Since I do legal move generation I can do the pins for half price
>>>>>>- I either have or can use the pin data for one side in conjunction with
>>>>>>generating moves.  I just finished the routine.  My NPS dropped by just over 4%
>>>>>>on bench test psitions.  I've just started testing an hope to have some
>>>>>>indication if pin detection is a win, lose or draw in a few days.
>>>>>>
>>>>>>One aside - the pin detection is not always more accurate (or mine isn't).  In
>>>>>>the following position for the move Nxg5 the no-pin SEE correctly returns +1
>>>>>>where the pin-detection SEE comes back with -2.
>>>>>>
>>>>>>[D] 7k/4q3/8/6p1/4N3/5N2/8/4K3 w - -
>>>>>
>>>>>
>>>>>White is lost in 24 :-)
>>>>>
>>>>>Thanks,
>>>>>Eugene
>>>>
>>>>Really? This ending is only lost in exceptional cases - and it's certainly not
>>>>obvious that this is one of them.
>>>>
>>>>Vas
>>>
>>>Hi Vas,
>>>
>>>Are you sure? It seems to me that this ending (Q vs. NN) is generally won for
>>>the queen. Maybe someone with the TB could check...
>>>
>>>Best regards - Munjong.
>>
>>Yes - but there exist some complicated zugzwang positions, even in the middle of
>>the board. I guess here black can already force one of them.
>>
>>Vas
>
>Could post some NNvsQ draw positions (with no fork in 1 move :o) ), please ? i'm
>very interresting in ...

If you like these sorts of positions, I'd highly recommend "Secrets of Pawnless
Endings" by J. Nunn. He does a good job trying to figure out the themes from the
TB results. Of course many times the theme is that you need to count 20 moves
ahead ... :)

Vas



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