Points fall into three groups: those on the fourteen channels, which have a standard location and belong to a channel; the extra points, which are named and located but belong to no channel; and the ashi points, which are simply where the patient hurts.
Their indications follow three rules. A point treats what lies near it, which is why local points are used for local problems. A point treats what lies along its channel, which is why a point on the hand treats the face. And some points have effects that follow neither rule, such as the influence of GV14 on fever or of PC6 on nausea. Recognising which of the three is operating is the basis of point selection.