Helpmate in 2; either side begins

H. Albertz and K. Henke
Die Schwalbe 1948

Helpmate in 2
One solution with White to play, One solution with Black to play
(Helpmate: Both sides move collaboratively to checkmate black in the required number of moves)

Originally posted by BigDoggProblem
H. Albertz and K. Henke
Die Schwalbe 1948
[fen]4k2r/8/8/8/2Q4p/8/8/4K2R[/fen]
Helpmate in 2
One solution with White to play, One solution with Black to play
(Helpmate: Both sides move collaboratively to checkmate black in the required number of moves)

a) white to move
Qxh4 0-0
Qh7#

b) black to move
... Rh7
0-0 Re7
Qc8#

Originally posted by Mephisto2
a) white to move
Qxh4 0-0
Qh7#

b) black to move
... Rh7
0-0 Re7
Qc8#

This is probably the easiest problem of the 8 I posted, but the mutual castlings are a nice touch.