Figure 2.1.6.3[White to move]

A color scan or a look at the White knight's circle of moves turns up a potential fork to be had at e6, and again its potential should not be obscured by the presence of White’s queen there. The question is whether the queen can make a move that will force Black’s response, giving him no time to prevent the fork Ne6+ a move later. First you look for a check, but it turns out that most of the squares from which the queen can attack the king―e7, e8, f6, f7, g8, d6—result either in (a) the queen being captured by Black’s king or queen, which ruins the fork, or (b) the king simply moving, which likewise ruins the fork. But if you persist you come up with 1. QxR+. If 1. …RxQ, then 2. Ne6+, forking king and queen; and if not RxQ, so much the better: after 1. ...Ke7, White can play QxRc7+ and has still more fun from there.