White almost seems able to mate with Qe8, but not quite; the king can escape. So he experiments with other checks, and after seeing that the knight on d7 is pinned he plays Qb6+. Now notice that since Black has no safe place to move his king, he must interpose something, and his only option is Qc7. Suddenly we have the familiar pattern now under examination: White’s queen attacks Black’s, which in turn is guarded only by its king. As soon as the pattern comes into view, look for an additional check to try to loosen Black’s queen. This naturally leads to 2. Re8+, KxR; 3. QxQ—and then White takes Black’s bishop or knight next move.