Skakbladet 3/2003, Nr. 1316c
Korrektur von Nr. 13162 in Skakbladet, Juni 2002, S. 19
The bishop at f6 is a promoted pawn. This can only have happened at
g1. (After c1L, the bishop would have forced the white king to move
after a check at d2.) The move g2-g3 occured only after the promoted
bishop returned via h2, g3 and h4. So the black pawn f7 went to g1 via
the g-file and the h-file, capturing three white pieces on the way.
The last missing white piece is the white bishop f1, which could only
get out after g2-g3 had been played. The white pawn e3 came from d2,
f4 came from h2, and f5 came from c2, all together capturing six black
pieces. (The other missing black piece was the bishop f8, which was
captured on its original square.)
All captures of black pieces must have occured before White played
g2-g3, because they were needed as waiting moves during the advance
of the pawn f7 and the return of the bishop g1. (Otherwise, White would
have lost his right to castle.)
Black's last move cannot have been the capture of White's white-squared
bishop, because no black piece is standing on an appropriate white square.
So White does not have a legal last move, if there were further moves
after g2-g3. (All tempo moves had been used up before.) Therefore, g2-g3
must actually have been White's last move, and it turns out that the
white bishop f1 must have been captured before by a black knight on
its original square. So the very last move was made by Black, playing
White's very first move wasn't with a knight, because he didn't have
any. It also wasn't with a pawn, because all of his pawns' first moves
had to be captures, except for g2, which however, could only move very
much later. So his first move was with a rook; and since the rook at
h1 hasn't moved yet, White's first move was Ta1-b1.
Interesting things began to happen after White captured a black knight
(or the black queen) at e3, letting out his queenside pieces.
This retrograde analysis may be clearer if a position is given which
might have occured 7 moves ago.
Then roughly the following happened: 1. Dh2 h3 2. Dg1 h2 3. cxd3 hxg1L
4. dxe4 Lh2 5. gxf4 Lg3 6. exf5 Lh4 7. g3 Le5.