Dongui Bogam_29_Breathing of the Embryo

[胎息法]
[Methods of Breathing of the Embryo]

眞詮曰, 人在胎中, 不以口鼻呼吸, 惟臍帶繫于母之任脉, 任脉通于肺, 肺通于鼻. 故母呼亦呼, 母吸亦吸, 其氣皆于臍上往來. 
Commentaries of the Perfected(眞詮) says, "When a fetus is in the womb, it does not breathe with its mouth and nose. The umbilical cord is connected with the mother's conception vessel. The conception vessel itself is connected to the lungs and the lungs to the nose and hence the fetus exhales when the mother exhales and inhales when the mother inhales. Qi goes in and out through the navel this way."

天台謂, 識神托生之始, 與精血合根在于臍. 是以人生時, 惟臍相連, 初學調息, 須想其氣出從臍出, 入從臍滅. 調得極細, 然後不用口鼻, 但以臍呼吸, 如在胞胎中, 故曰胎息. 初閉氣一口, 以臍呼吸, 數之至八十一, 或一百二十, 乃以口吐氣. 出之當令極細, 以鴻毛着于口鼻之上, 吐氣而鴻毛不動爲度. 漸習漸增, 數之久可至千, 則老者更少, 日還一日矣. 葛仙翁每盛暑, 輒入深淵之底, 十日許乃出, 以其能閉氣胎息耳. 但知閉氣, 不知胎息無益也.
Supporting the Sky (天台) says, "When the spirit comes out, relying on life, it joins with the essence of the body at the navel, becoming the root." Like this, when a baby is born, it is connected to the mother solely by the navel. Therefore, when learning the breathing method (調息) for the first time, one must think that one's breath comes out from one's navel and goes into the navel again. After leveling the breath off, as if one is in the womb, one does not use one's mouth and nose and uses only the navel when breathing; hence the name the breathing of the embryo (胎息). At first, one holds his or her breath and breathes with the navel, counting to 81 or 120 before exhaling. Exhaling should be done softly so that even if a feather of a wild goose is put on one's mouth and nose, it does not move. If one can count to 1000 by practicing daily and gradually increasing the count, he/she gets younger daily even after he/she becomes old. Whenever the weather was hot, Ge Xianwong (葛仙翁) used to dive into the bottom of a deep pond and come out after 10 days; this was because he could hold his breath and breathe by the way of the breathing of the embryo (胎息). Nevertheless, if one only knows how to hold his/her breath and not how to breathe by the way of the breathing of the embryo (胎息), it is only futile. 

養性曰, 胎息者, 如嬰兒在母胎中, 氣息自在, 上至氣關, 下至氣海, 不假口鼻之氣. 故能閉氣不息, 能入深泉, 旬日不出也.
The Nurturing the Spirit (養性) says, "The breathing of the embryo (胎息) is breathing freely at one's will like a baby in the mother's womb, having the breath reach up to the qi bar and down to the lower danjeon field, and still not using the mouth and nose. That is how one can hold his breath and not come out from a deep pond for ten days." 

又曰, 內觀之要, 靜神定心, 亂想不起, 邪妄不侵, 氣歸臍爲息, 神入氣爲胎, 胎息相合, 混而爲一, 名曰太乙.
He also said, "The point of self-reflection is to tranquilize the spirit, stabilize the heart, not allow disturbing thoughts to arise or evil and absurd things to enter the body. When qi returns to the navel, it becomes respiration; when spirit goes into qi, it becomes the fetus. It is also called taeeul (太乙, the meaning of great and slow movement) because respiration and fetus get mixed and become one.