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 < *"ʔəm" compares with Burmese "ʔum" "overcast; cloudy", Adi "muk-jum" "shade", and Lepcha "so'yǔm" "shade"; and is probably cognate with Chinese "àn" < *"ʔə̂mʔ" "dim; gloomy" and "qīn" < *"khəm" "blanket" "Yang" < *"laŋ" compares with Lepcha "a-lóŋ" "reflecting light", Burmese "laŋ" "be bright" and "ə-laŋ" "light"; and is perhaps cognate with Chinese "chāng" < *"k-hlaŋ" "prosperous; bright"; "bǐng" < *"braŋʔ" "bright"; "liàng" < "*raŋh" "(pale) light"; "lǎng" < "raŋʔ" "brilliant light"; "míng" < "mraŋ" "bright, become light, enlighten". Schuessler surmises that those items either are areal words (cf. Tai "plaŋ" "bright") or belong to an Austroasiatic word family (cf.