The Huang Di Neijing describes correspondence between the articulations of the body and the cosmos, specifically between heaven and earth and the upper and lower parts of the body:
Heaven is round, earth is square; people’s heads are round, their feet are square and thereby correspond to them. Heaven has the sun and moon, people have two eyes; Earth has nine regions, people have nine orifices. Heaven has wind and rain, people have joy and anger; Heaven has thunder and lightning, people have the notes and sounds. Heaven has four seasons, people have four limbs. Heaven has five tones, people have the five depots; Heaven has six pitches, people have six palaces. Heaven has winter and summer, people have cold and hot [ailments]. Heaven has ten days, people have the hands ten fingers. Heaven has yin and yang; people have man and wife. The year has 365 days; the body has 360 joints. Real sages cultivate [their persons] without benevolence and righteousness, govern without merit or fame, are at ease without needing rivers and seas, attain longevity without guiding and pulling, forget everything but lack for nothing, placid without limit, things of value follow upon them benevolence (ren), trustworthiness (xin), loyalty (zhong) and filiality (xiao).
Daoist writings emphasize the importance of both mystery and emptiness, and all-embracing unity, which the Daoist must actively preserve by meditation practices, techniques of preserving the essence (bao jing).
Huang Di neijing ling shu 71.2, 446, cf. Wong Ming 1987
(ch. 15, 537, cf. Graham 1986a, 265; Watson 2013, 119).