Now a nifty application of our current concept. Black toys with 1. …Qc1+ and sees that it's met with 2. Rf1. But then 2. …Qe3 gives check, requiring White’s king to move back to h1. (If White plays Rf2 instead of Kh1, White mates with QxR+ and then Qf1#.) This forcing of the king into the corner is a standard idea for producing a smothered mate; now we have reached the rough position explained in the previous frame. Black can mate by dancing his knight in the familiar fashion: 3. …Nf2+; 4. Kg1, Nh3++; 5. Kh1, and then comes the traditional sacrifice of the queen: 5. …Qg1+, RxQ (White's rook has been sitting on f1 since White’s first move in the sequence); 6. Nf2#.

The interesting thing about the position is that Black couldn't have started with Qe3 because it would not have given check (and so would have allowed White time for Qf8#). Instead Black starts with 1. …Qc1+, the only function of which is to force White’s rook down onto the back rank so that 2. …Qe3 will give check and control the action.