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Subject: Re: Most Commonly Underpromoted Piece

Author: Mike S.

Date: 13:38:05 02/26/06

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On February 26, 2006 at 16:08:09, Howard Exner wrote:

>Would this honor go to the Knight? Do others here agree?
>Although I've witnessed underpromotion to a Rook and Bishop these are typically
>found in composed endings.

Yes, I think R/B are not required for playing games nor for normal analysis (of
practical games), because cases where it really makes sense to promote to R or B
are extremely rare. In contrast, N promotion are rare too basically, but OTOH
appear in numbers that I would mean an engine is somewhat incomplete if it can't
do it (although it will probably not noticably impact ratings).

>Should a program have the knight as the second priority after the Queen?
>Is there a way to smartly implement underpromotion ?

I cannot comment on implementation and programming of this. - I guess though,
that it's not a matter of special priorities but just an additional possible
move which leads to a much different material balance anyway, and therefore the
queen is always prefered if there are no good reasons to not prefer it :)

I think it could be useful for a "complete" analysis mode, to do without R/B
underpromotion if the engine is playing, but to add an option to switch it on in
addiotion to Q/N for analysis mode. Or simply an option to switch this on or
off. This would enable fans of studies to analyse positions where that matters
and at the same time, avoid unneccesary time consumption in normal situations.

>Finally, does anyone have a rook or bishop underpromotion theme from an actual
>game?

In most games where that happenend, the underpromotion wasn't really required
(i.e. if the new piece needs to be captured immediatly no matter if Q or R). I
remember having seen some examples, some if which contained R or B promotions
"with sense," at Tim Krabbés site who dedicated a chapter exactly to this topic:

http://www.xs4all.nl/~timkr/chess2/minor.htm

I think it is not unusual to do only Q/N promotions, to save time in chess
programs. AFAIK Wchess did it like that, and probably many others do now. It may
also be handled differently depending on where in the tree the position
appears... but that's something programmers can give better info about.

Regards,
M.Scheidl



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