In earlier work we have studied many ways of loosening a piece or square. One is to capture the guard. Another is to make a capture on the contested square, allow a recapture, and see if the piece left standing there is loose. Still another is to ask whether the guard also is protecting something else that you might take. That last method is our focus in this chapter. We will be looking at cases where you want to take something. It's guarded. We ask whether the guard also is guarding any other targets—another piece, or a mating or forking square. If it is, the guard is said to be overworked: it has too many defensive responsibilities. The next question is which of the two things it protects you should try to take first. Different move orders can have different consequences, as we shall see. You may be able to distract the guard from the first target by taking the second one; or you may be able to take one of them for free.
Notice that there are two general ways to see the pattern described here. You can examine your opponent’s defenses with an eye out for any pieces with more than one defensive job; or you can spot a target you want to take (a piece or a square), see that it is guarded, and ask whether the guard has other responsibilities. It amounts to the same thing either way, and you will want to be at home with both trains of thought.
We start here with simple cases where a single guard protects two enemy men. We will look at quite a few of these. It is important to be comfortable with them, as this theme arises often.
In this first position to the left, be aware of the enemy pieces you attack and what prevents you from taking each of them. White’s a1 rook attacks the bishop on a3, which is protected only by Black’s queen. White’s c3 bishop attacks the knight on f6—which also is protected only by Black’s queen. The logic of the opportunity becomes clear: the queen can't effectively protect both pieces; if you take one, the other should be left loose. Thus White starts with BxN, using the less valuable of his two attackers first and inviting it to be taken. If Black recaptures QxB, his bishop on a3 is loose and White takes it with his rook.