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The Connection of the Six Channels with the Five Viscera and the Six Bowels - Part One

by Lorraine Wilcox

Part One


How are the six channels associated with their organs? Why is the lung associated with the hand taiyin channel? This article contains an analysis of six-channel theory from both the Mawangdui medical manuscripts and the Yellow Emperor's Inner Canon. There is also a comparison between various chapters of the Inner Canon that assign each of the viscera to a modified version of the four images of the Yijing (taiyang, shaoyang, taiyin, shaoyin).

The focus of this article will be on the relationship between the yin-yang designation of the five viscera according to Elementary Questions, Chapter 9 (see note 1) and the six-channel names. This will involve some speculation on my part. I justify this based on the advice of Appended Sentences, Part 1, Chapter 2 (see note 2), which tells us to play with things.

The Mawangdui manuscripts and the six-channels (see note 3)

In 1973, a number of medical manuscripts were discovered in Mawangdui's Tomb 3 in Changsha, Hunan Province. These hand-copied manuscripts were buried in 168 B.C.E. with the occupant of the tomb, a local member of the elite class. These manuscripts are among the oldest medical writings we have today that were not copied generation after generation (see note 4). The significance of this is that during the copying process, manuscripts are edited and changed, sometimes by errors in copying and sometimes on purpose. Even though the Inner Canon is as old as or older than these manuscripts, it was continuously revised up through the Tang and Song dynasties, and therefore it was constantly filtered over the generations.

Two Mawangdui manuscripts are of particular interest here: Moxibustion Canon of the Eleven Yin and Yang Vessels (see note 5) and Moxibustion Canon of the Eleven Vessels of the Foot and Forearm (see note 6). Both describe the pathway of the main channels and the ailments attributed to them. The only treatment recommended in either of these two books is moxibustion on the affected channel, although they do not specify the exact location. In fact, no acu-moxa points are explicitly mentioned anywhere in the Mawangdui manuscripts.

These eleven channels are described as beginning in the region of the hands or feet and all of them travel proximally. They do not connect 'like a ring without end.' They do not have detailed internal pathways and do not correspond to a particular organ. Both manuscripts discuss eleven channels; the channel we now associate with the pericardium is absent (see note 7).

The Foot and Forearm Vessels manuscript uses six-channel terminology for all eleven vessels. The Yin and Yang Vessels manuscript uses six-channel terminology for most of the vessels, but the three arm yang vessels correspond to parts of the anatomy (see table 1).

Foot and Forearm VesselsManuscript Yin and Yang VesselsManuscript
foot greater yang vessel greater yang vessel
foot lesser yang vessel lesser yang vessel
foot yang brightness vessel yang brightness vessel
foot lesser yin vessel lesser yin vessel
foot greater yin vessel greater yin vessel
foot reverting yin vessel reverting yin vessel
forearm greater yin vessel forearm greater yin vessel
forearm lesser yin vessel forearm lesser yin vessel
forearm greater yang vessel shoulder vessel
forearm lesser yang vessel ear vessel
forearm yang brightness vessel tooth vessel

Table 1. The names of the eleven vessels.

These channels occupy similar positions to the channels with the same names in Magic Pivot, Chapter 10. For example, the foot greater yang vessel is on the yang (outer) side of the leg, and is the most posterior of the yang channels. The foot yang brightness vessel is on the yang side of the leg, but is the most anterior of the yang channels.

Figure 1. The Yang Channels of the Legs (Zhang 1991, page 771)

Although a few of the vessels in the Mawangdui books meet with an internal organ, they are not necessarily the same organ that is associated with the channel in Magic Pivot, Chapter 10. For example, the forearm greater yin vessel goes to the heart in both Mawangdui manuscripts on the eleven vessels; it is associated with lungs in the Inner Canon. The Yin and Yang Vessels manuscript tells us the foot greater yin vessel corresponds to the stomach, but this is the only case of an organ correspondence (see note 8) (in the Magic Pivot, the foot greater yin channel corresponds to the spleen). In conclusion, it appears that the channels were associated with their six-channel names before they were associated with the organs.

Harper (1998, p84) speculates that the six-channel names developed to describe the progression or severity of disease. As evidence, he cites Death Signs of the Yin and Yang Vessels (see note 9), another Mawangdui manuscript. This short text says that the three yang vessels are associated with heaven and their ailments are unlikely to cause death. However, the yin vessels are associated with earth and are the 'vessels of death.' The idea that the six channels represent a progression of disease is also presented in later texts such as Elementary Questions, Chapter 31, and the Discussion of Cold Damage (Shanghan Lun).

I would like to stipulate that while Harper, Unschuld, and other scholars seem fairly certain that the Mawangdui texts are representative of the medicine at the time, I am not so sure. It is true that no archaeological find from this period discusses the internal pathways of the channels in detail, the acu-moxa points, and acupuncture using the filiform needle. However, it may be that the texts found represent only a certain type of literature. All these manuscripts are from the tombs of elite noblemen who were interested in the tradition of nourishing life. They themselves would not have practiced acupuncture, so they would not have needed such texts. A doctor of acupuncture would not have belonged to this elite class, so he would not have had such a magnificent grave site. A doctor's sons may have retained his precious books in order to continue the family occupation rather than placing them in the grave.

If we can believe the reports of Sima Qian (see note 10), Chunyu Yi did practice a recognizable form of acupuncture at that time. Could he have been unique? Or is it just that his books and the books of his contemporaries in the same profession have simply not survived or not been located as yet?

If it is true that the channels were associated with their six-channel names before they were associated with the organs, then at some point, sages and doctors must have observed these connections and must have had a reason for associating each organ with a specific six-channel name.

The yin-yang correspondences of the five viscera

Elementary Questions, Chapter 9 gives a yin-yang designation for the five viscera. It uses a terminology that closely resembles the four images in change theory, with the addition of a fifth category for the spleen. It says:

"The heart is the root of life, the changes of the spirit. Its flower is in the face. Its fullness is in the blood [and] vessels. It is greater yang within yang. It communicates with the qi of summer.

The lungs are the root of qi, the dwelling of the corporeal soul. Their flower is in the hair. Their fullness is in the skin. They are greater yin within yang. They communicate with the qi of autumn.

The kidneys govern hibernation. They are the root of sealing and storing. They are the dwelling of essence. Their flower is in the hair of the head. Their fullness is in the bones. They are lesser yin within yin. They communicate with the qi of winter.

The liver is the root of stopping extremes. It is the dwelling of the ethereal soul. Its flower is in the nails. Its fullness is in the sinews. It is used to engender blood and qi. Its flavour is sour. Its colour is dark green. This is lesser yang within yang. It communicates with the qi of spring.

The spleen, stomach, large intestine, small intestine, triple burner, and urinary bladder are the root of the food granary. They are the dwelling of construction [ying]. They are called the 'vessel.' They are able to transform the dregs and sediments. They pass on the flavors so that they can enter and exit. Their bloom is in the four whites of the lips. Their fullness is in the flesh. Their flavor is sweet. Their color is yellow. They are in the category of reaching [or extreme] yin. They communicate with earth [element] qi"
(see note 11).

Organ Designation Notes
heart greater yang
within yang
The lungs and heart are located within yang because they are in the upper body. They are also considered 'greater' because they are located above.
lungs greater yin
within yang
kidneys lesser yin
within yin
These organs are considered more yin because they are in the lower body. The kidneys and liver are also considered 'lesser' for this reason. The spleen will be discussed separately below.
liver lesser yang
within yang (see note 12)
spleen in the category of extreme yin (see note 13)

Table 2. Yin-Yang association with the viscera in Elementary Questions, Chapter 9.

Let's examine the designation for each organ in more detail. Organs located above are considered 'within yang': the heart and the lungs. Since both the lungs and the heart are located in the upper body, the position of honour, they are also considered 'greater.' Organs located below are considered 'within yin': the liver, spleen and kidneys. Since these organs are located in the lower body, they are generally considered 'lesser.' The heart is considered greater yang because it is associated with fire, the most yang element, the most hot and bright. It represents the sun, which was often called greater yang (taiyang) in ancient times.

According to Elementary Questions, Chapter 8 (the chapter just before this one), all the organs are like government officials. The heart is the emperor, who receives the position of honour. Both the sun and the emperor are located in high places, and fire is the element that flares up the highest. In addition, when speaking of yin-yang, fire and water are often used as a metaphor. Of course, fire is the metaphor for yang. For all these reasons, the heart is greater yang within yang.

The lungs are considered greater yin. They are the prime minister, in a high position (greater), but lower than the emperor; thus they are yin. They are metal, bright and reflective, representing the brightness of the heavens or the reflected light of the moon, but not the sun itself. The moon was often called greater yin (taiyin) in ancient times. It rules the night, the time of yin. The metal element is considered more yin than fire; metal is heavy and condensed. It sinks and does not rise. Metal belongs to the west, where the sun sets. For all these reasons, the lungs are greater yin within yang.

The liver is considered lesser yang. It is the military general, but the general must always be under the command of the emperor and prime minister; so it is located below and considered lesser. As wood element, the liver likes to rise up, but it is not as yang as fire. That is why it is lesser yang within yin. The kidneys are considered lesser yin. As Laozi reminds us, water, being yin, seeks a lower position. It does not contend like the emperor, minister, or general. Perhaps this is why Elementary Questions, Chapter 8 says, "The kidneys are the official who makes strength. Ability and skill come out of them" (see note 1). They don't have a high position like the heart, liver, or lungs. The kidneys are more concerned with their own affairs than with achieving a high position in the world. This is why the kidneys are lesser yin within yin.

The above four organs are each given one of the four images of the Book of Changes [yijing]. However, there are five viscera, so a fifth 'image' must be created. The spleen is considered 至陰 zhiyin. This term needs some discussion. 至 Zhi can mean 'to reach, to arrive at; very, the extreme, greatest, the best.' (Mathews 1943, p135). We could translate it as reaching yin; since the spleen is just below the diaphragm, it is located just as we reach the yin part of the body. Zhiyin can also refer to long summer, the season associated with the spleen (see note 15). This is the end of the yang seasons (spring and summer) and the beginning of the yin seasons (autumn and winter). It is the time when the seasons reach their yin phase. Zhiyin could also be translated as extreme yin since earth is the most central. The centre is yin, while the periphery is yang. Therefore, when considering the centre versus the periphery, the spleen is the most yin of all the organs.

In addition, spleen earth is often called kun (坤) earth by the old masters of Chinese medicine. The Yijing trigram kun is extreme yin because it has three yin lines; it is pure yin. According to the before-heaven sequence, the other yin trigrams have yin and yang lines mixed (xun, kan, and gen). The other female trigrams only have one yin line each (the daughters: xun, li, and dui). In addition, kun is in the most yin position, the north, in the pre-heaven sequence of the trigrams. And kun is associated with 地 earth, which has a primary association with yin. In a sense, the spleen is both earth element (土) and the earth of heaven and earth (地). The association of the kun trigram with the spleen is another reason it can be called extreme yin.

In Elementary Questions, Chapter 9, greater seems to refer to the amount of authority or high position: the sun and the moon, the emperor and the prime minister. It does not necessarily refer to the amount of yin or yang. The kidneys are more yin but have less authority than the lungs: they are lesser yin. The spleen has more yin but less authority than the lungs (see note 16): it is extreme yin. The liver, as the only viscera located below that has a high position, is given a yang designation, even though it is lesser. These yin-yang designations refer to the organs, not the channels. Yet they are reminiscent of the six-channel names. It seems that these designations arose independently of the six-channel names, since most chapters where they occur do not discuss the channels (see note 17).

If the conclusions drawn from the Mawangdui medical manuscripts turn out to be accurate, the channels did not originally correspond to specific organs. When the organs were connected with the channels, the sages needed to rectify the yin-yang designations of the organs with the six-channel names. The relationship between the two will be discussed below.

The relationship between the yin-yang designation of the five viscera and the six-channel names

This section contains speculation based on the ideas presented above. Within the five viscera, some are considered yin and others are considered yang. However, when we bring in the eleven or twelve channels, we can only consider the channels associated with the viscera as yin; the yang channels must be reserved for those associated with the bowels. So the lungs can retain the title of greater yin and the kidneys can retain the title of lesser yin. The spleen needs a new designation as there is no channel named extreme yin. The heart and liver were considered yang among the viscera, but now need to be associated with a yin channel. As far as the 'within yang' or 'within yin'f part of the organ designation, those organs 'within yang' (the lungs and heart) are given to the channels of the hands, as are the channels of their paired bowels. The relationship or the internal-externally paired organs holds, even though there are no bowels located in the upper body. Those organs 'within yin' (liver, spleen, and kidneys) are associated with yin channels of the legs, as are the channels of the bowels that are paired with them.

Greater yang (太陽 taiyang)

As an organ, greater yang refers to the heart. Its image is of the sun. Greater yang cannot be used for the heart channel, however, because the heart and the heart channel are considered yin when all the organs and channels are taken into account. Among the five viscera, some can receive a yang designation. But once the viscera and the bowels (or their channels) are considered, we cannot use yang for the heart. However, we can transfer the designation of greater yang to a closely associated channel, the small intestine. It is also fire element, and it traverses the upper back, one of the most yang aspects of the body. The small intestine and heart have some parallel functions: the heart (which stores the spirit) must take in information, digesting and transforming it. It must separate out the true from the false. The small intestine performs a similar function with the nutrients and fluids taken in by the body.

The three yang channels of the arm are connected to organs that are located or are rooted in the lower burner (see note 18). It would seem logical that their channels would be located on the legs, but this cannot be. If that were the case, the yang channels on the arms would have no organ to which they could correspond. However, the trade-off is that the yang channels of the arm are distant from their associated organ; thus the need for a lower he-sea point. However, it is important that the three burners are well connected with each other. By pairing the heart with an organ in the lower burner, the body is unified. This also applies to the heart's six-channel pairing with the kidneys; the heart abandons the greater yang designation, which it lends to the small intestine, and joins the kidneys as lesser yin. By making a close relationship between heart and kidneys, fire and water, above and below, the body is unified.

As an organ, the heart is greater yang, but as a channel, it becomes lesser yin. Since the heart is fire element, the emperor, and is located above, it is quite yang, which makes it less yin than other viscera such as the spleen or lungs. The relationship between fire and water is further strengthened through the greater yang channels, the small intestine and urinary bladder. Both of these channels are greater yang because they traverse the most yang parts of the body: the upper back, neck and head.

Lesser yin (少陰 shaoyin)

The kidneys are the lesser yin organ because they are located below the diaphragm, as discussed above. The kidney channel, being yin, is able to retain its lesser yin designation. It is paired with the heart channel, which is less yin because it is fire and connected to greater yang (the heart's own designation as an organ and the internally-externally paired channels, the small intestine and urinary bladder).

Organs Heart: greater yang taiyang
Kidneys: lesser yin shaoyin
Channels Heart:

Table 3. Designations for heart, small intestine, kidneys and bladder.

Greater yin (taiyin)

As an organ, greater yin refers to the lungs and the lung channel can retain this designation. It is the image of the moon. It is the metal of heaven, the bright reflective canopy above us. The lungs, as the prime minister, must have something to govern; they must have a connection to one or both of the burners below them. Thus they are connected with the spleen. We have seen that the spleen was called zhiyin, extreme yin. This is not one of the six-channel names. However, extreme yin must be related to greater yin; it could not be lesser yin and still be extreme. In addition, this stabilizes the relationship between the upper and the middle burner. We can call the spleen kun earth and the lungs qian heaven. In change theory, kun earth is associated with humility. The spleen humbly offers the fruits of the earth (food qi) up towards the lungs, which also take in the bounty of heaven qi (air). Intake and gathering are yin characteristics. These two organs take in all the post-heaven nourishment of the body. Therefore, they are the most yin, greater yin. In addition, the lungs connect to the lower burner through the large intestine, the other metal channel. This will be discussed below. The emperor (heart) and prime minister (lungs) are in the upper burner, but the emperor connects to the lower burner through the small intestine and kidneys. The prime minister connects to the middle and lower burners through the large intestine and spleen.


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