[Retros] Introduction to Proof Games
elkies at math.harvard.edu
Fri Jan 8 15:55:48 EST 2010
"Werner Keym" <w.keym at gmx.net> writes:
> A different thing is that a promotion to R or B
> is more attractive than to Q.
That's true in play-to-win chess, and in related genres such as
studies or direct-mate problems, where one usually wants to promote
to the most powerful piece possible, whence a strictly less powerful
promotion on either side is a surprise. In helpmates, White R or B
promotion is much more valuable than Black (indeed Black Q promotion
may be the paradoxical choice). In retros it seems hard to propose a
general rule. Certainly if the diagram shows three or more White Rooks
then a wR promotion in the retroplay is no surprise...
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