It first appears in Ge Hong's (4th century CE) Baopuzi 抱朴子 (行品 chapter), which says xiuzhen practices characterize a daoren 道人 "Daoist".
Xiushen 修身 and xiudao 修道 are more common synonyms of xiuzhen that occurred centuries earlier in pre-Han Chinese classic texts.
Both these anatomical charts with Daoist Neidan symbolism derive from the earliest diagrams attributed to Yanluozi 煙蘿子 (fl.
Contrasted with the Neijing tu, the Xiuzhen tu pictures the meditator's body in a front view rather than side, and includes a longer textual portion, which describes Neidan practices, lunar phases, and Leifa 雷法 "Thunder Rites" associated with the Zhengyi Dao movement of the Tianshi Dao "Way of Celestial Masters".
The elements that distinguish this chart from the Neijing tu are mainly related to the Thunder Rites (leifa) – in particular, the spiral at the level of the kidneys, the nine "orifices of hell" at the base of the spine, and the three curls at the top of the head that represent the three primordial breaths according to the Tianxin zhengfa tradition.
In particular, the human figure is surrounded by thirty black and white circles that represent the days of the lunar month, one of the models of the Neidan "fire phases".
The trigrams arranged around the figure (Zhen ☳, Dui ☱, Qian ☰, Xun ☴, Gen ☶, and Kun ☷) represent the six stages of the lunar cycle, each of which is made of five days.