The first thing to note about the position is that Black is in what an OTB player would call zugzwang, since if it were his move, there is a mate set against every possible black move (check for yourself!). This makes the problem what is called a complete block. It follows that White needs a waiting move. This is
1.Bb3
Now let us see some of the mating variations. If
1...Bb7
White has [Likewise, after 1...Rb7
there is 2.Rc6#
, as now, the BR on c6 interefres with the bishop's diagonal from a8. This mutual interefernce of the BR and BB is the key theme of the problem, and is known as the Grimshaw theme, after the 19th century English composer Walter Grimshaw, who first showed it.
; But, to use the catchphrase of a particularly dreadful English comedian of bygone years, "There's more". If we look at the to-right-hand corner of the board, we see another BR/BB combination, and sure enough, we have another Grimshaw here: if 1...Bg7
2.Qxf7#
; whilst if 1...Rg7
2.Qe5#
; There is even a third Grimshaw concealed in the position, although this time not a pure R+B Grimshaw, but a Pawn Grimshaw: if 1...f6
2.Qe4#
because the Pf6 stops the defence Be5),; whilst if 1...Bf6
2.Qg4#
since the Bf6 stops the defence 2...f5]
2.Re7#
because the Bb7 interefres with the BR's action along the 7th rank. *