The original meaning is that the earth rotates once, which means that the day and night cycle once; Later, it was extended that the internal qi circulates in the body along the two channels of Ren Du, that is, the internal qi starts in Xiadantian, passes through perineum, anus, passes through the tail, ridge and jade pillow along the Du Meridian, reaches the mud pill on the top of the head, then separates from the ears and cheeks, reaches the tip of the tongue, connects with Ren Mai, and returns to Dantian along the middle of the chest and abdomen. Because of its relatively small scope, it is called Tian. Also known as Meridian, Sunday, Picking Ridges to Fill the Vacancy, Fire and Water ji ji, Jade Liquid Returning to Dan, etc.
Internal alchemy requires internal qi to circulate in the body according to meridians. In the early days, it was called "the golden liquid belongs to Dan" (Song Dynasty. Weng Baoguang's preface to Wu Zhen), also known as River Wagon Handling (On Ming and Lu), borrowed the astronomical term "Sunday" (Tian Li by Ming and Wu Songyang) from the viewpoint of "the correspondence between man and nature". Others called the route of this action "route" (Yuan's Talking on the Table). Xiao Zhoutian means that the internal qi starts in Xiadantian, goes up against Du meridian, goes down along Ren meridian, passes through Tailu, Jiaji point, Jade Pillow, Upper, Middle and Lower Dantian, and Upper and Lower Queqiao, and the upper Queqiao is in the perineum and. Inner alchemy pays special attention to Ren Du's two veins. For example, Li Shizhen pointed out in Eight Classics: "Ren Du is the son of a man, and it is also noon. It is the way to raise and lower the word "Yang Huo Yin" in Danjia, far away from the place where fire and water meet. " Therefore, Xiao Sunday is also called Meridian Sunday, or take the ridge to fill it, leaving the ridge for copulation, fire and water ji ji, and the heart and kidney intersect. At noon, when Yin Qi began to move, Yang Qi began to descend and Yin Qi began to sprout. Therefore, the meridian represents the sun and moon of the celestial body, the heart and kidney of the human body, the barrier in the hexagrams, and the north and south in the orientation. In the Yuan Dynasty, Yan Zhi Jr. said it could be represented by gossip the day after tomorrow. Because Xiao asked to return to nature the day after tomorrow on Sunday, Neidan theory is guided by gossip the day after tomorrow. So the focus is on Kan and Li. In the gossip the day after tomorrow, it is in the position of noon, water, fire, sun and moon, so it has the above name.
When practicing Xiao Sunday's kung fu, the feeling of internal qi flowing in the governor's veins began when he was alive. When I was alive, I went down to my abdomen to produce small medicines, also called true seeds. Then he began to supervise the circulation of the two veins and correctly mastered the requirements of entering the yang fire, retreating the yin and bathing. On Sundays, he sometimes decides to put the words "SHH", "H", "Hum", "Blow" and "Hip" together, inhale from each nose in turn, and recite each sound six times, which is 36 times.