Figure 2.1.10.4[White to move]

Start by finding every check White can give. There are four: Qxe6, QxB, Nf6, and Ne7. The first two lose the queen and have no good follow-ups, but Nf6+ is interesting; Black can’t respond with BxN because his bishop is pinned by White’s queen. So Black must move his king. Now ask if White will have another check after the king moves. Notice that whether the king goes to h8 or f7, White can play QxB+. Either way Black has the reply KxQ. So then his king will be where his bishop now sits, on g7—at last on a dark square; and your knight will be on f6. Since your only plausible attacking piece is your knight, you naturally are on the lookout for a fork. In the resulting position you find it at e8. After taking Black’s queen, you’re up a bishop.