The Daoqiao Tan 道窍谈 Discourse on the Gateway to the Dao

Daoqiao Tan (Discourse on the Gateway to the Dao) was written by Li Hanxu, whose original name was Li Yuanzhi, styled Pingquan, with the literary names Hanxuzi and Changyi Shanren. He was a native of Leshan County, Sichuan. He often traveled to places like Mount Emei, where he once encountered an immortal master who imparted daoist formulas to him. He then changed his name to Xiyue and practiced in seclusion for several years, becoming well-versed in alchemical methods.

In Daoqiao Tan, Li Hanxu points out that a person of virginity, who is in a state of innate primal chaos (huntun) and has complete spirit and essence, is called a "person of supreme virtue" (shangde). Such a person can attain the path of immortality directly through pure and tranquil cultivation, without the need for return and restoration (fanhuan) or unblocking the meridians (tongguan). For those who have lost their virginity, their essence and qi have dissipated, and they can no longer be considered virgins. They must open the orifices and unblock the gates (zhankao kaiguan), activate the mysterious gate (xuanmen) and clear the path, so as to return to the origin and restore the true self. Therefore, the main purpose of inner cultivation throughout the book is to return to the origin and resume one's destiny (guigen fuming).

The book requires that during the stage of foundation building and self-cultivation (zhuji lianji), one should rely on the assistance of the "other family" (bijia). It states: "Inner cultivation of the self (neilian ji) means using the lead (qian) from the other family to refine the mercury (gong) of one's own family, so that they can assist and preserve each other."

Li Hanxu summarizes the core of inner alchemy cultivation as the method of concentrating the spirit (ningshen). He says in the book: "When essence transforms into qi, this essence is in the yinqiao (Yin Bridge) point, and when it is reversed into the Purple Mansion (zifu) for refinement, it turns into qi. When qi transforms into spirit, this qi is in the Yang Furnace (yanglu), and when it is reversed into the Yellow Court (huangting) for refinement, it turns into spirit... To reversely cultivate the primordial essence (yuanjing), one must first concentrate the spirit. When the spirit is concentrated, qi gathers; when qi gathers, essence is generated. Because when spirit and qi interact and unite (jiaogou), primordial essence is naturally produced. This essence is the water of the Heavenly One (tianyi zhi shui), which is Ren in Kan (the trigram of Water), also known as the mother qi or outer essence. A learner uses the mother qi to nurture the child qi, and uses the outer essence to supplement the inner essence—this is the practice of the same kind (tonglei shigong). The child qi is the heart qi, and the inner essence is the heart essence. The learning of acquired cultivation (houtian peiyang zhi xue) proceeds from the outside to the inside. Therefore, one must first cultivate the outer medicine to return to the inner medicine.

There is also the principle that spirit transforms into essence and essence transforms into qi—this refers to the transformation of fluid in the Crimson Palace (jiangong), which flows back to the Primordial Sea (yuanhai), and after the fluid transforms into qi, it circulates through the River Chariot (heche). There is also the principle that qi generates essence and essence generates spirit—this refers to the ascent of white clouds and the descent of sweet dew (ganlu), drawing out the yang from Kan to supplement the yin in Li (the trigram of Fire)."

This is the basic principle of the Western School (xipai) alchemy methods of Li Hanxu.