Difficulty 23

The three yin and three yang channels of the hands and feet—what are the lengths of their pathways? Can you let me know? It can be done. The pathways of the three yang channels of the hand run from the hand to the head, each five feet in length; five times six gives thirty feet total. The pathways of the three yin channels of the hand run from the hand to the chest, each three feet five inches in length; three times six gives eighteen feet, and five times six gives three feet, totaling twenty-one feet. The pathways of the three yang channels of the foot run from the foot to the head, each eight feet in length; six times eight gives forty-eight feet. The pathways of the three yin channels of the foot run from the foot to the chest, each six feet five inches in length; six times six gives thirty-six feet, and five times six gives three feet, totaling thirty-nine feet. The two qiao channels of the foot run from the foot to the eye, each seven feet five inches in length; two times seven gives fourteen feet, and two times five gives one foot, totaling fifteen feet. The du channel and the ren channel each measure four feet five inches; two times four gives eight feet, and two times five gives one foot, totaling nine feet. The total length of all pathways is sixteen zhang and two feet; this is what is referred to as the lengths and numbers of the twelve channels. There are twelve channels and fifteen collateral vessels—where do they begin and where do they end?

It is like this: The channels are what move blood and qi, communicate yin and yang, and thus nourish the entire body. They originate from the middle burner, first infusing into the hand taiyin channel and the hand yangming channel; the hand yangming channel then infuses into the foot yangming channel and the foot taiyin channel; the foot taiyin channel infuses into the hand shaoyin channel and the hand taiyang channel; the hand taiyang channel infuses into the foot taiyang channel and the foot shaoyin channel; the foot shaoyin channel infuses into the hand jueyin channel and the hand shaoyang channel; the hand shaoyang channel infuses into the foot shaoyang channel and the foot jueyin channel; the foot jueyin channel then returns to infuse into the hand taiyin channel. Additionally, the fifteen collateral vessels all follow their main trunks, like a ring without end, circulating and reciprocally irrigating and distributing, ultimately converging at the cunkou and renying locations, where they are used to judge various diseases and determine life or death.

The medical classic says: Clearly understand the ends and the beginnings, and the principle of yin and yang can be established. What does this mean?

It is like this. What is called the ends and the beginnings is the outline of the channels. Cunkou and renying are the places where yin and yang qi assemble and penetrate, causing the channel qi to circulate like a ring without end, thus they are called the beginnings. What is called the ends refers to the severance of the qi of the three yin and three yang channels; severance leads to death, and death each has its own manifest form, thus it is called the ends.