This position is structurally similar to the first one in this section, though it looks a little different because of the compression of pieces at White’s end of the board. Take it apart the same way. Black would like to play QxQ, but White’s rook on d1 guards the target. Since the queen’s defender is on the back rank, test its stability by putting one of your pieces there: Rb1+. White’s only legal response is RxR—leaving his queen to be taken with QxQ. White’s d1 rook was overworked.