Figure 4.5.1.4[White to move]

The examples so far in this chapter all have involved enemy kings that had wandered out a couple of ranks from their starting positions; they also have involved skewers imposed by bishops. That’s no coincidence: the king has to be out a few squares on a diagonal before it can lie between a bishop and anything else. But other pieces can give skewers, too. The pattern of Black’s king and rook on the same rank is unremarkable in itself, but it can lend itself to a rook skewer in the right circumstances—such as those shown here. Notice the layout; or examine any checks White can offer and find just one—Rd8. Since the square is protected by White’s bishop, Black wouldn't be able to capture the rook with his king, nor would he be able to interpose anything. The king would have to move, and in moving it would leave the loose rook on h8 exposed, allowing White to play RxR.