Dear Dr. Jiang,
I thought I understood wei qi, but after reading several books recently, I realized how much contradictory information exists on this subject. Some texts say wei qi originates in the lungs, some that it originates in kidney yang, still others that it comes from the turbid qi in the intestines. Could you clarify this matter?
Defender of Clarity,
Dear Defender of Clarity,
You are quite right. There is a lot of misunderstanding concerning wei qi, even in China. Part of the problem is that the circulation of wei qi has become confused with its formation and function.
Chapter 18 of the Ling Shu talks about the formation of wei qi as follows :
"Man's qi is retrieved from grain (gu). Grain enters the stomach and (the refined part) is sent to the lung (on its way to) the five zang and six fu, so they can all receive their portion of qi. The clear (qing) part is ying qi, the turbid (zhuo) is wei qi."
This passage establishes the stomach and the ingested grain therein as the starting point for all qi, both ying and wei, and the lung is simply a transfer point for this qi as it moves along to the other organs. The relationship between wei qi and the lung does not stand out as special or exclusive, and the lung is not said to form or create wei qi. Furthermore, there is nothing here to support the claim that wei qi originates in the intestines, which are not even mentioned. The distinction being made between "clear" and "turbid" is one of quality, not point of origin. In this context zhuo means not only "turbid," but also "intense" or "strong," like a strongly brewed cup of tea. The author is trying to draw a connection between the strong, fierce qualities of wei qi and the strong, concentrated qualities of the digestate from which it is drawn.
This analogy occurs again in Chapter 43 of the Su Wen:
"Rong (= ying) qi is refined from the essential qi (jing qi) of grain and water... wei qi is the fierce qi (han qi) from grain and water."
Both passages affirm that, while representing different refinements of the digestate (i.e., "essential" vs. "fierce," "clear" vs. "turbid"), ying and wei are nevertheless formed from the same precursor: "grain and water." Since grain and water must be transformed by the stomach and spleen, it is the middle burner that forms wei qi, not the lung.
This relationship between the spleen and wei qi is highlighted in Chapter 36 of the Ling Shu, which describes the role of each of the five zang as follows:
"Among the five zang and six fu, the heart is the sovereign...the lung is the prime minister, the liver is in charge of planning, the spleen is in charge of defending (wei), the kidney is in charge of supporting."
This passage designates the spleen, not the lung, as the ruler of defense. Nowhere in the Nei Jing does it state that wei qi is formed in the lung or originates in the lung. So why do so many modern texts emphasize the lung when talking about wei qi? Presumably, it is because the lung and wei qi are both said to control the surface of the body. Indeed, a case can be made that the diffusing function of the lung assists the spread of wei qi. But while the lung may help to spread it, the true genesis of wei qi lies in the middle burner, and it is here that the healer must focus if he or she is trying to affect this substance.
If we ignore the middle burner, we could end up with ineffective therapy when treating wei qi deficiency. Two formulas that are commonly used to tonify wei qi, bu zhong yi qi tang and huang qi jian zhong tang, have as their primary emphasis the tonification of the middle burner. Even yu ping feng san includes bai zhu, which tonifies spleen qi. The most important herb for tonifying wei qi is huang qi, an ingredient in all the above formulas. But this herb also tonifies spleen qi. Even in acupuncture, point combinations for tonifying wei qi almost always include needles or moxa on St 36 (a common formula is St 36, LI 4, UB 12 and UB 13). From this, we can conclude that there can be no tonification of wei qi without tonification of the middle burner.
I am aware that some modern authors claim that kidney yang is the root source of wei qi. This seems to be the result of a misreading of chapter 76 of the Ling Shu. This chapter states that the wei qi emerges from the eyes at sunrise and enters the urinary bladder channel, from which it flows successively through the remaining yang channels the rest of the day. At sunset it enters the kidney channel, traveling successively through the remaining yin channels during the night. Both the urinary bladder and kidneys belong to the lower burner, so the lower burner is, in a sense, a starting point for wei qi circulation. There is nothing in this chapter, however, that would suggest that wei qi is formed in the lower burner; the text is exclusively devoted to a description of circulation (xing). In clinical practice, kidney yang tonics are not used to tonify wei qi, and the lower burner is not targeted in any of the above formulas. While kidney yang is sometimes tonified as a root treatment in extreme cases of wei qi deficiency with deficiency cold symptoms, the therapy must ultimately target the middle burner if it is to succeed.
So, DoC, if you want to tonify wei qi, you have to focus on the middle burner, especially the spleen. If you bring the lung into the treatment, it will only be to assist the spreading of wei qi or to treat concurrent lung symptoms. Kidney yang does not play a direct role in the production of wei qi, and tonifying kidney yang is only justified if there are clear signs of kidney yang deficiency, such as back and knee pain, cold limbs, etc. Even in these cases, the spleen would have to be tonified as well.
Edited with the assistance of John Pirog, MSOM.
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