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
Yang Yin Yang, not willing to accept Ge's commission, pretended to be ill by holding cow blood in his mouth and then spitting it out. In 529, after Ge Rong had been defeated by the Northern Wei paramount general Erzhu Rong, Yang Yin returned to the Northern Wei capital Luoyang and was made a low level imperial official in the administration of Emperor Xiaozhuang. Later that year, when Yuan Hao the Prince of Beihai claimed imperial title under support from Liang Dynasty and captured Luoyang briefly, forcing Emperor Xiaozhuang to flee, Yang Yin convinced his cousin Yang Kan to remain loyal to