Figure 4.4.6.6[White to move]

Put together the lessons of the last few positions and you have this one. Ask what White attacks. His bishop on h3 attacks Black’s knight on d7. His rook on d1 attacks nothing as such, but is aimed down the d-file where Black has a pawn, a knight, and a rook. White’s power directed at the d-file suggests that he consider play there and keep pinning possibilities in mind. What stands in the way of a good pin? White would need to clear his own pawn on d4 out of the way, but that can be done easily enough with a capture (d4xe5). The other problem is that behind what Black has in front on the file (his pawn at d6), he has a piece that is protected. As we know, a routine motif in creating a relative pin involves loosening one enemy piece that lies behind another. Can Black’s knight on d7 be loosened or replaced with a loose piece? Of course; that is the significance of White’s bishop on h3. White plays BxN, and when Black replies RxB he now has a loose rook on d7 behind his d6 pawn. The pawn would be pinned if White’s own pawn were out of the way, so now it's time for d4xe5. Black recaptures f6xe5. White has created a classic relative pin on Black’s pawn at d6, so he takes what it is supposed to protect: Nxe5, winning a pawn and improving his knight's position.

Notice how this position combines the ideas in this section: accounting for all of the attacks White can make, and seeing how they might be coordinated; identifying a latent pinning possibility on a file where White directs force, even though the possibility is obscured because White’s own pawn is in the way and Black’s screened piece is guarded; methodical loosening of the piece on the screened square with an exchange; and then violent evacuation of the file by White’s pawn that had been in the way. All this to win a pawn.

Incidentally, if you’re alert you might wonder whether Black can escape trouble by replying to White’s initial BxN with e5xd4, taking a pawn and making a counterthreat against the knight on c3. After this move it looks like Black will be able to take either White’s knight or his bishop next move, and without stepping into a pin in the process. But White has a clever answer: Bxc6, winning back the pawn and creating a fresh threat—perhaps a counter-counter-threat—against Black's bishop on b7. Now Black has to play BxB (or else suffer it himself), after which White has Nxd4. In this variation White thus wins a pawn, just as he does with the primary sequence considered above.