There are three hundred and sixty-five acupoints, corresponding to the days of a year. Each has a fixed location and a fixed name. Xi Gu (valleys, referring to the depressions between muscle bundles) refers to the separation of large and small muscles, connected to bones and arising from them. Fen Bu (divisions) refers to the partitioning of the skin.
The Fu Luo (superficial collaterals) within the Pi Bu (skin divisions) are divided into the Three Yin and Three Yang meridians; they have courses that are either smooth or reversed, each possessing its own order. This indicates that the Four Seasons and Yin-Yang of Heaven and Earth possess complete longitudinal and latitudinal frameworks, corresponding to the interior and exterior of the human form, all having surface and depth relationships. (Qibo replied: The East generates Wind. (Wind is the Qi of spring generation in the East, thus governing the generation of wind.) Wind generates Wood. (Yin and Mao years belong to Wood, which is generated by the Qi of spring.) Wood generates Sour taste. (The Five Elements of the earth generate the Five Yin flavors.) Sour taste nourishes the Liver. (The generation of Yin essence fundamentally lies in the Five Flavors, thus Sour taste nourishes the Liver. This statement refers to how the internal Zang organs and external tendons, bones, skin, and flesh all receive the Qi and flavors of the Four Seasons and Five Elements to generate one another, hence it is said that the correspondence between interior and exterior all involves surface and depth relationships.) The Liver nourishes the Tendons, and the Tendons nourish the Heart. (The essence-Qi of the Liver nourishes the Tendons, and the essence-Qi of the Tendons nourishes the Heart. The internal Zang organs correspond to the Qi of the Five Elements.)