Figure[White to move]

Here is a challenging study. The snug alignment of Black’s king and queen on the same diagonal should jump out at you as the makings of a possible pin. Since the pinned piece would be a queen, the piece doing the pinning would need protection; Bc6 therefore wouldn’t work. Do you have any protected squares on the king and queen’s diagonal? Yes: b5. If White’s light-squared bishop were there, it would pin the queen and also attack Black’s rook on a6, which you notice (because you always notice these things) is loose. So the remaining question is whether you can maneuver your bishop to b5 fast enough to achieve the pin. Look for a route to that square for the bishop and you see just one: Bd3, then Bxb5. Bd3 doesn’t check or capture anything, but since it’s the natural move to pursue the pin you imagine it and see what response it would provoke. Let’s see: Would Black move his king to avoid the coming pin? If he does, then White still plays Bxb5 and forks the rook and queen. Would Black move his queen or rook so that he could take White’s bishop when it lands on b5? He could, but since the bishop has protection from a pawn White still would win at least the exchange.

Black ends up having no good reply to Bd3 despite having a move he can use to defend against the coming Bxb5. His real problem is that b5 is both a pinning square for White and a forking square of a type familiar from the chapter on bishop forks (notice the familiar triangle between b5 and Black’s rook and queen—and the king behind the queen). Plus b5 is protected by a White pawn. The square is so strong for White that even with a move’s notice Black can’t avoid being hurt by it. Black best response to Bd3 is Rb6; then he can reply to Bxb5 with RxB and merely suffer a4xR—losing the exchange and a pawn.

This position does not involve clearing lines. It just involves moving the bishop over to the pinning square in two moves, a sequence made possible by some quirks of the position. The first lesson is the importance of realizing when a pinning square exists; once you have found or created such a square, you can turn your attention to ways of getting a suitable piece there. Second, the position shows the importance of thinking about moves that direct your pieces where you want them to be and thinking carefully about what your opponent would be able to do in reply. Sometimes his options will be more limited than you might expect.