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 Yin Yang Jia (Yin and Yang School) Needham concludes "There can be very little doubt that the philosophical use of the terms began about the beginning of the -4th century, and that the passages in older texts which mention this use are interpolations made later than that time." In spite of being used in a modern context to justify egalitarianism under the notion of both yin and yang being "necessary", in practise the concept of yin and yang has led to justification for China's patriarchal history. Particularly under Confucianism, yang (as the sun principle) is considered superior to "yin" (the