[Retros] First example of "reverse mate" theme

Pastmaker at aol.com Pastmaker at aol.com
Sun Oct 10 08:06:35 EDT 2004

In the late 1970s Problemist had a tournament for the composition of
"minimals" -- problems in which White has only King and one other unit. Then a
neophyte retroanalyst, I naturally tried to get one with a valid e.p. key, sending a
couple of examples to the judges. The tournament award, published in the
July 1980 issue has an example by Kahl and Mortensen from Die Welt 1967 that
anticipated what was kindly referred to as my "valiant attempts to accomplish the
same task".

For our purposes (to the extent this is of any interest) the Kahl and
Mortnesen example did not have the property at question in this recent
correspondence, that White have no other legal move but e.p. capture resulting in checkmate.
One (or maybe both, I don't recall) of my submissions did have that
property, but, having been anticipated by Kahl and Mortensen for pusposes of the
tourney, they were not published, and I don't have ethem any more.

But, if anyone is interested, it is possible to construct a minimal that also
has the property that the minimalist side's only legal move is 1. Pxp.e.p.,
mate (the move being justified retroanalytically in the sense that Black
demonstrably must have made the two-square advance on its last move). (One might
call this a "mate only e.p. minimal".)

I remember one more feature that may be of some interest. Being even
clumsier then than now in realizing tasks, I was not able to achieve the e.p. minimal
without at least one promoted Black Unit. Kahl and Mortensen's superior
setting was an e.p. minimal without promoted force, but was not (and why should it
have been?) a mate only e.p. minimal.

So, the challenge, I suppose (and I have not tried in the last 25 years), is
to compose a mate only e.p. minimal with no promoted force. Personally I will
refrain, confident that others will succeed.

Tom Volet

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