Figure 3.3.10.5[White to move]

No doubt you see the kernel of a discovery: White’s knight masks his bishop on the h1-a8 diagonal. But not much can be done with it; the more fruitful thing to notice is that White has a bishop bearing down on the king on the other long diagonal—and that White can create the kernel of another discovery, and also give check, by moving his knight to f6. That move both masks the bishop with the knight and forces Black’s king over to h8, putting a target into place for a discovered check. Now the knight will have two unfettered moves, so it heads toward Black’s queen via his rook: NxR, followed next move (after Black avoids the check from White’s bishop) by NxQ.

The only fly in the ointment is that after White plays Nf6+ at the outset, Black can end the threat with NxN. How to remedy this? With a preliminary exchange: 1. QxN, BxQ, and now play continues as described above with Black’s defender of f6 eliminated. The queen sacrifice is costly, of course, but it pays off soon enough.