lateral thinking - Horde of bishops

This has got to be the coolest chess puzzle I have ever seen. Shamelessly stolen from here (Which is actually linked from the help center, which is how I found this) which links here. I don't believe anybody has posted this before as a puzzle though.

The question: Can white win in this position?

Answer

Try to solve this before reading below! (No, really!)

The answer is

Yes

Because

  1. B4f6  a6
  2. Ba1   a5
  3. Bdg5  a4
  4. Bgf6  a3
  5. Kc3   Kxa1   (or: 5. ...Kb1  6. Kb3 a2  7. Kc3 Kxa1  8. Kc2#) 
  6. Kb3+  Kb1
  7. Ba1   a2

  8. Kc3   Kxa1
  9. Kc2#

all Black's moves (other than 5) forced.
Thanks to Gareth for an enlightening comment in The Sphinx's Lair.