The so-called "reverse" means that the Du meridian starts from the perineum, passes through the three levels of the back, reaches the Baihui above the head, and then goes down to Dantian from the front. This is called Sunday, which is just the opposite of the meridian route proposed by the doctor above. Taoism combines innate essence with acquired qi (subtle water) to form "medicine", which is called "essence" and "early Qing" Then enter the stage of practicing qi and spirit in the big week, which is called "Guan Zhong"; Finally, in the final stage, the practice of Shangguan was still empty and entered the Tao body. Among them, Sunday's operation is mainly based on the second pulse of Ren Du, and this mechanism of rising first, then falling, and then rising is called the symbol of rising yang and falling yin, which is to get through the second pulse of Ren Du. The first pass is September, the middle pass is October, and the upper pass is nine years, which shows that practice is not easy. However, this training idea clearly shows the qualitative change process from body to mind, from tangible to intangible, and from material to spirit, which is concrete to follow. As for the possibility of external force "opening the second pulse of Ren Du", although Taoist priests with profound internal strength can be seen in the classics, that is, releasing external gas to treat diseases, except for martial arts novels, there is no theory of external gas opening the second pulse of Ren Du in the canon. Treating diseases by regulating qi was a helpless countermeasure against diseases under the medical environment at that time; Nowadays, medical technology is one hundred times more effective than regulating qi, and it should be exaggerated to say that it is easy to get through the second pulse of Ren Du with the help of external force.