I think you need to lure the king to b6.  1. Be3+ allows 1...Kb8 , and I think the king will avoid being mated in five by, for example, 2. Na5 Ra7, and now the king has shelter (although very temporary) on a8.

What?????????Sacrificing two knights... okay I get the point there's a mate but it can be pretty risky if you're in this position with time trouble.

But what is when a black rook go 4. d8?

The bishop wouln't be able to checkmate.

Or am I overseeing something???

but hey cool puzzle

Being that 1. Na5 isn't a check, it gives black time to play 1...Rab8 and the king temporary shelter on a8.  I think you need to lure the king into the fire and force it to b6.

wow!!

ha ha ha

5. Bd2#

tough puzzle.  It is hard to see that many moves ahead.

tough one!

not that easy!

Pretty tough...

good one

  I thought the same thing at first "the puzzle is wrong!" but The annoying 4...ba2 stops it - then i realized that after Bxb3 axb3 discovers a mate very tough puzzle.

that was a very good puzzle

beautiful...

hard

4.a4 can be played.