The Retrograde Analysis Corner

Fairy Promotions

Eric Angelini, 02 Aug 1995

I finally found the ref. of a fairy promotion which was later captured, leaving
the board with no fairy pieces: i don't know if it is an example fitting in
your (interesting :-)) discussion of the few last days.

Bedrich Formanek - 3rd Prize - S V CSTV C - October 31, 1966

+--+--+--+--+--+--+--+--+
|  |  |  |  |  |  |  |*B|
+--+--+--+--+--+--+--+--+
|  |  |  |  |  |  | P|  |
+--+--+--+--+--+--+--+--+
|  |  |  |  |  |  |  | B|
+--+--+--+--+--+--+--+--+
|  |  |  |  |  |  | P|*K|
+--+--+--+--+--+--+--+--+
|  |  | P|  |  |  |  |  |
+--+--+--+--+--+--+--+--+
|  |  |  | B|  |  |  | K|
+--+--+--+--+--+--+--+--+
|  |  | P|  | P|  |  |  |
+--+--+--+--+--+--+--+--+
|  |  |  |  |  |  |  |  |
+--+--+--+--+--+--+--+--+
8+2       Checkmate in 1#

Here is how the author of the book ('Jean Bertin' - 'Histoires extraordinaires
sur 64 cases' - Grasset&Europe Echecs Editor - p.135/6), together with the
author of the pb analyze:

What was last move by Black? BK h5 coming from g6; but in g6 the BK was in
check - by WB d3 which could not give check by himself;

so a discovered check was given by ... either a Grasshopper S moving from f5 to
h5, or a Camel (they move [1,4] like Knights move [1,2] - in french the name is
'Chameau' notated CH) moving from e4 to h5; in both cases the BK g6 took after
the check the W piece on h5;

we come then to the diag.

so: a) if the last moves were  n-1) Sf5-h5+   KxSh5
                THEN W mates immediately with g7xBh8=S##;
    b) if ...                  n-1) CHe4-h5+   KxCHh5
                THEN ...            g7-g8=CH ##

Nice, is it not?

... and a few pages before, there is a 1962 (!) pb with a 3x promotion (in
Grasshopper, Bishopper or Leo) but with a Maximum-Selfmate condition.

Richard Sabey, 2 Aug 1995

Thanks to Eric Angelini for Formanek's problem involving proving that a
grasshopper or camel had previously existed. A camel is a (1,3)-leaper, not a
(1,4)-leaper as Eric had said.

In English, we use G for grasshopper. S might mislead Germans (S =
Springer, the German for Knight), and sometimes S is used for Knight in
English, though I prefer N.

I'd append "2 solutions" to the stipulation, because the two possible RA
arguments lead to different mating moves.