Figure 5.4.1.6[White to move]

The note at the end of that last position is a hint to the solution of this one, which is a little harder because White has nothing under attack at the outset. Still, notice the precarious position of Black’s rook: it’s way out on the board, not loose but protected by a queen from far away. Perhaps the protection can be disrupted. That would be a visual approach to the position; a different route would be the trusty one of examining any checks you can give and their consequences. White has two with his rook and two with his queen; the most interesting would be any check that also threatens the rook, which brings you to Qd8+. Since the e-file is off limits to Black’s king, he has to play Kc2 or Kc3. The most significant property of those moves is that either of them blocks the path from Black’s queen to the rook and so leaves the rook loose. White takes it next move.