Chinese sun and moon mirrors being hung round the neck, or because necks are concave things. Liu An's (c. 139 BCE) "Huainanzi" "Masters of Huainan", which is a compendium of writings from various schools of Chinese philosophy, was the first text to record "fangzhu" dew-collectors. Two "Huainanzi" chapters metaphorically use "sun and moon mirrors" to exemplify "yang" and "yin" categories and elucidate the Chinese notion of "ganying" "cosmic resonance" through which categorically identical things mutually resonate and influence each other. The "yángsuì" 陽燧 "burning-mirror" is "yang", round, and sun-like; the "fāngzhū" 方諸 "square receptacle" is "yin", square, and moon-like. The first context describes "yangsui" and
Yin and yang (winter and summer), the landscape (north-facing shade and south-facing brightness), sexual coupling (female and male), the formation of both men and women as characters, and sociopolitical history (disorder and order).There are various dynamics in Chinese cosmology. In the cosmology pertaining to Yin and Yang, the material energy, which this universe has created itself out of, is also referred to as qi. It is believed that the organization of qi in this cosmology of Yin and Yang has formed many things . Included among these forms are humans. Many tangible dualities (such as light and dark, fire and water, expanding and