1. Bf6

(The Bishop moved from h4 to f6.) This is a sophisticated use of the tactic of interference. Black has too many possible replies to list them all, but White will reply with one of the following: Re5#, Rf4#, or Nd2#. Here are some examples:

1. ... Bxf5 2. Nd2#

1. ... Bxf6 2. Rf4#

1. ... Bxh6 (or Rxf6 or Rd8) 2. Re5#