What does White attack? Not much, it might initially seem; his c1 rook and his bishop each attack a pawn, and both pawns are protected. But combine these inquiries with the other studies we have made elsewhere. Find a chance for a fork by stepping back from the board and looking for a geometrical pattern in Black’s position; or look for any checks you can give; or imagine those pawn captures just mentioned. In any of these ways you want to see that Bxd5+ is a pretty triangular bishop fork of Black’s king and rook. The move won't yet work, of course, because d5 is guarded by a knight. But the first thought then is to destroy the guard if you can. White plays NxN, and after the recapture a5xN the fork Bxd5+ works nicely.
This position is no different from several studies in the chapter on bishop forks showing how they can be set up by loosening the forking square. The point of including the position now is to show again how the ideas considered here relate to our earlier work, and also to serve as a reminder that when you look for points you attack in the enemy camp you start with enemy pieces at which your forces are aimed, but do not end there: look as well for sensitive squares—e.g., forking squares and mating squares. More on this later.