14+12. Matt in 2 Zügen
We will show that the BK has moved and thus that Black cannot castle.
White can then mate via 1. Rd1, anything; 2. Rd8++.
The Wh. KB was captured on its own square, so a WR was captured on
e6. The Bl. KB was captured on its own square, so the Bl. QB, the Bl.
Q, and a Bl. R were captured on b3, c3, and e3.
The capture on e6 must have happened before the Bl. c-pawn moved to
c6, otherwise the Bl. QB could not have gotten out to be captured on
b3. Thus, to allow his R out, Wh. made a capture before Bl. did. What
piece could Wh. have captured? It couldn't have been a Bl. R, since
neither R could get out until after the capture on e6 created an opening
in the Bl. pawn structure. It couldn't have been the Bl. QB, so it must
have been the BQ. But, before the capture on e6, the Bl. Q-side pawns
had not moved, so the only way the BQ could get out was via f7. This
means that the BK must have moved, so Bl. cannot castle.
Now, the BQ was captured through d2xc3, because a capture through
f2xe3 would not have let the Wh. QB out. Hence White's O-O-O is broken
too because the captured Wh. Rook really is from a1, or had to disturb
its King. This explains why the dualistic solution 1. O-O-O ?? fails.
Solution by Philippe Schnoebelen and Roger Lipsett