Figure 6.1.10.3[Black to move]

You can start by spotting the battery for Black, this time on the c-file; and once more you see a knight on the same file—an opportunity, not an impediment. True, White has a queen on c2 that would block the path of your heavy pieces to the back rank. But you play with the discovery anyway and see that the knight can give check with Nd3. This invites Black to play QxN—but then the queen no longer blocks the file, and Black mates on c1 because he has two heavy pieces aimed at the square against one Black defender of it (the rook on a1). If White instead moves his king to d1 he gets mated even more quickly with QxQ+. Yet White must address the check somehow, and since it is given with a knight there is no way to interpose; all that’s left is e2xN, forfeiting the queen to QxQ.

This position can be understood as calling for a straightforward discovered attack against a loose queen; but of course you have to see the back rank mating possibility to grasp why White can’t put out the fire easily with QxN.