Figure[White to move]

The striking feature of this position should be the open (devoid of pawns) f-file, and particularly the kernel of a discovery that White has there: his knight masks his queen. The Black target on the other side—the knight on f7—is protected. Well, but by what? The bishop on e8. So the discovery can be executed and the guard eliminated with the same blow: NxB. Black recaptures RxN, and now the f7 knight is loose, permitting QxN with the gain of a piece.

There are two points to take away from this frame. The first is the importance of keeping in mind different tactical tools and ways you can use them together: the logic of the discovered attack can be joined with the capture of a guard in powerful ways.

The second point is that it is common during a game for minor pieces to be aimed at each other. One of your knights or bishops often will be pointed at one of your opponent’s knights or bishops, with the pieces on both sides having enough protection, and with the pieces at stake similar enough in value, to make the situation seem stable. Remember when you see such a pattern that if either side pulls the trigger and so forces a trade of pieces, the consequences can be very significant—not for the pieces exchanged, but for anything they used to protect. Minor pieces frequently are used as supports for other pieces, which after a capture and recapture may be left loose and thus become good targets for forks or discoveries. So when either side has an unexecuted opportunity to capture a minor piece, think habitually about whether such a capture would have the side effect of removing a guard.