Now let's look at a few positions where some element of the discovered check—open lines or appropriate targets—has to be manufactured. The ideas behind the methods used here will be familiar; only the context is any different from what has come before, but seeing how the old ideas look in new settings will make them easier to see in real time.
Find the makings of a discovered attack for Black in the position to the left. His rook blocks his bishop along the g1-a7 diagonal. The bishop is aimed toward White's king but is blocked by the pawn at f2. Black can't capture the pawn and cause an interesting recapture, so try another idea: capturing something the pawn protects and thus forcing it to move on the recapture. Viz.: Black plays QxB, inviting f2xQ. If White plays the recapture, Black's discovered check has been nicely prepared. All that remains is to find a good target the d4 rook can reach in two moves. Rd8+ unmasks check; then after White saves his king, Black has RxQ.
Take a moment now to appreciate the threats that Black faces in this position and how the sequence just described would bear on them. White has three pieces aimed near Black’s king: his queen, rook, and bishop. Look at White’s checks and you see that he is poised to play Rxc7+. Black would have to play BxR. Now comes the follow-up check QxB+, forcing Black’s king onto a8; and finally White mates with Qb8. Fortunately it’s not White’s turn to move! The beauty of QxB for Black is not only that it wins a piece by threatening a discovered check; it also defuses White’s threat against c7 by adding a guard to the square (Black’s queen) and by taking out one of the attackers against it (White’s bishop).