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?

• No, because black king would always be able to move to the white square? Proly you can do stalemate, but not win. Jun 7, 2017 at 10:40
• @JanIvan Without pawn, true. But... :) Jun 7, 2017 at 10:43
• @ZizyArcher Depends on where Black pawn ends. If there, there is only one way with enemy bishop moving to A2. If Black pawn has to end here - you wait till black pawn is on A3, then you move bishop from A1/H8 line, and next move after you see King A1+pawn A2, you move it back to A1/H8 line. Jun 7, 2017 at 10:53

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

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.

• Why is Black's move 5 forced? Jun 7, 2017 at 11:04
• Not very cute when you had it solved one hour before it was posted… Jun 7, 2017 at 12:07
• @JanIvan I don't know what you mean. I didn't have an answer until just a few minutes before I posted mine.
– Rubio
Jun 7, 2017 at 12:15
• Nice :) How did you solve it so fast though? Jun 8, 2017 at 6:00