Fang Hui was a native of Yin during the reign of Yao. Yao invited him to serve as a village official, and he refined and ate yunmu (a mineral), which was also given to villagers who were ill. He lived in seclusion in Wuzuo Mountain — a practice of Yunyou, the Taoist tradition of wandering and dwelling in nature. At the end of Xia Qi's reign, he became a court official, but was kidnapped by others and locked in a room, where he sought the Dao. Fang Hui transformed and managed to escape, then used his name Fang Hui to seal his door shut. At the time people said that if one obtained a single pill of clay from Fang Hui and used it to coat a door, the gate would remain permanently closed.

Fang Hui Yisheng lived in seclusion at Wuzuo. He chewed yunying (a mineral) and dwelled with his mind in a state of emptiness and stillness — embodying the cultivation of the Tao through inner stillness. The heavily guarded gates opened by themselves. Seals were changed and doors sealed, yet they remained permanently closed.