The Tan Chuduan 谭处端

Tan Chuduan (1123-1185) was a native of Ninghai in Shandong Province during the Jin Dynasty.

His original given name was Yu, with the courtesy name Boyu. After embracing Taoism, he adopted the religious name Chuduan and the courtesy name Tongzheng; his Taoist title was Changzhenzi (Master of Eternal Truth), and he was commonly known in the world as "Changzhen Zhenren" (Venerable Eternal Truth).

In his youth, he was fond of reading classics and historical records. He was skilled in cursive and official script calligraphy, and particularly adept at writing the two characters "gui" (tortoise) and "she" (snake). It was said that his calligraphy of these two characters seemed to possess a dynamic quality of "flying, soaring, and transforming" (a description of the characters’ vivid, lifelike style). Taoist practitioners regarded these calligraphy works as precious treasures.

In the 7th year of the Dading era (1167), he became a disciple of Wang Chongyang and converted to the Quanzhen (Complete Perfection) Sect of Taoism. In the 8th year of the Dading era (1168), he followed Wang Chongyang to Kunyu Mountain, together with Ma Danyang, Wang Chuyi, and Qiu Changchun (Qiu Chuji). They opened and resided in Yinxia Cave (Cave of Mist and Rosy Clouds) on the mountain.

In the 9th year of the Dading era (1169), they moved to Jinlian Hall in Ninghai. After Wang Chongyang passed away, Tan Chuduan lived in seclusion in the regions around the Yi and Luo Rivers. Later, he resided in Chaoyuan Palace in Luoyang, where he founded the Nanwu Branch of the Quanzhen Sect. He was counted among the "Seven True Ones of the North"—the core seven disciples of Wang Chongyang who propagated Quanzhen Taoism.

Tan Chuduan died in the 25th year of the Dading era (1185) at the age of 63. In the 6th year of the Zhiyuan era of Emperor Shizu of the Yuan Dynasty (1269), he was posthumously awarded the honorific title "Changzhen Yunshui Yunde Zhenren" (Venerable Eternal Truth of Clouds and Waters, Endowed with Virtue).

He composed nearly a thousand poems and songs for the world (works intended to spread Taoist ideas and resonate with ordinary people). These works were compiled into a book titled Shuiyun Ji (Collection of Clouds and Waters).