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 and establishing Northern Qi. Emperor Wenxuan made Yang Yin his prime minister and created him the Duke of Huashan, and during Emperor Wenxuan's reign, Yang served capably, finding appropriate officials for the key posts. Therefore, although Emperor Wenxuan, particularly late in his reign, turned violent and wasteful, the imperial government nevertheless functioned effectively. Yang was praised for remembering those who had helped him in the past, repaying them greatly, but not bearing grudges against those who had tried to hurt him. With Emperor Wenxuan, in his late years, accustomed to killing people for entertainment while he was drunk, Yang thought