This one is a step up in difficulty. What can White’s bishop do? Its checks don't seem to lead anywhere, but there are other attacking possibilities to consider as well: Bg5, attacking the Black bishop (barely worth noticing because it's a useless target); Bd2, attacking the Black rook; and Bxb6, attacking rook and bishop. This last move has the appealing look of a double attack, but again the bishop is an unsuitable target. This may be as far as you can go with initial reconnaissance; what you know is that (a) White has no double attack as yet; (b) if he is to make one, the most plausible place for it probably would be b6; and (c) a fork there might be doable if the Black king somehow could be moved onto the diagonal leading away from the rook toward d8. The next step is to experiment with whatever (other) checks White has available.

The only check White can give with another piece is Rd1+. How would Black respond? If he plays Ke6, White would be able to play RxB; the Black bishop would be the victim of a skewer. To avoid this fate Black would need to move the king not to e6 but to a square where it can protect the bishop: either Kc7 or Ke7. Then what? Again, the pattern that would then exist probably would be easy enough to recognize if you encountered it as an initial matter: With Bxb6 White has a double attack against the a5 rook and against either the bishop on d8 (if Black moved his king to e7) or against the king itself (if it was moved to c7). The fork still isn't quite there; White needs to perfect it by substituting the Black king for the Black bishop with RxB, to which Black responds KxR. Now Bxb6 at last wins the rook.