The classical source of the root-and-knot theory: the root lies at the extremities, the knot on the head, chest or abdomen.
Ling Shu (灵枢)Meridians and Points
ENGLISH TRANSLATION
The English is translated from the Chinese vernacular. The original text and its pinyin sit beneath each sentence in smaller type; hide them whenever you prefer to read the translation alone.
The taiyang channel roots at Zhiyin and knots at the gate of life. The gate of life here means the eyes.
Gen Jie describes each channel as having a root at the distal end of the limb and a knot somewhere on the head, chest or abdomen. The root is where the channel qi originates and where treatment is most effective; the knot is where the channel terminates and where its influence is felt.
This is the theoretical basis for the most characteristic feature of acupuncture point selection: treating a distant point on the hand or foot for a disorder of the head or trunk. It also explains why the five shu points, all of them distal, carry indications far beyond their anatomical location.
ANNOTATION
Gate of life (命门): here the eyes, not the Du vessel point. The Lingshu says “the gate of life is the eye,” meaning that taiyang qi gathers in the eyes.
Great forehead (颡大): the region from the root of the nose to the forehead.
Window cage (窗笼): the inside of the ear.
Bone shaking (骨繇): 繇 is read as 摇, joints slack and standing unsteady.
COMMENTARY
Root and knot, together with branch and root, qi street and the four seas, make up the spatial framework of channel theory. The reasoning behind the efficacy of modern scalp and auricular acupuncture can already be glimpsed here. If a practitioner memorises the root and knot sites of the twelve channels, then selecting points at a distance will have method and will not drift without anchor.