The Yu Dongzhen 余洞真

Yu Dongzhen was a figure in the late Southern Song Dynasty.

He wandered and traveled in Hangzhou, where he received the transmission of Taoist doctrines from the Southern Sect of the Golden Elixir School (Jindan School) from his teacher. With the tenet of "refining yin with yang, forgetting form and eliminating thoughts; naturally, when tranquility reaches its peak, yang arises; as yang grows, yin fades; when yin is exhausted and yang becomes pure, the immortal path is accomplished," he wrote The Chapter of Realizing the Profound (Wuxuan Pian), which has been passed down to later generations.