what is Fetal breathing 胎息？

Fetal breathing, also known as a method of Qi cultivation in the practice of Qigong, refers to the state where one can cultivate Qi to such an advanced level that they no longer need to breathe through their nose or mouth. Instead, the internal Qi within the abdomen circulates and permeates throughout the body, similar to how an infant does not breathe through its nose or mouth while in the womb.

The 'Taiqing Tiaoqi Jing' states: 'Fetal breathing is like an infant in the womb for ten months, nourished without eating and growing to maturity. The bones are fine, the tendons are soft, holding firmly with one's mind.' The 'Yanling Shengren Ji Xin Jiu Fu Qi Jing · Yangxiu Da Liao' says: 'If a person can follow the way of an infant in the womb by consciously cultivating internal Qi, holding firmly with one's mind, this is called fetal breathing.' Daoism, based on the theory of returning to the primal state from inversion, believes that when one cultivates Qi until there is no longer any breath in or out through the nose or mouth, and returns to the state of an infant in the womb, they can return to their original nature and achieve immortality. Therefore, fetal breathing is considered the most important and ultimate goal in Daoist cultivation for achieving immortality.