The liver belongs to wood, stores the blood, governs free coursing, opens at the eyes, governs the sinews, and has its bloom in the nails. Its humor is tear fluid, its mind is anger, and its voice is shouting. It stands in exterior-interior relationship with the gallbladder. It holds the Office of General.

Wood

木 mù in Chinese meant tree or wood, although in the modern language, 树 shù has replaced it in the meaning of tree. Trees are plants, so wood also represents plants in general. Trees and other plants provide fuel for fire and material for making shelter, tools, weapons, shields, paper, and even clothing. Many provide edible fruits.

Wood is the bending and straightening (木曰曲直 mù yuē qū zhí) is the classic description of the chief quality of wood. This refers to pliability and resilience that allows trees and plants to bend and sway in the wind to avoid being destroyed by it. These springy qualities are put to advantage in the design of the archer’s bow.

Wood thrives by orderly reaching (木喜条达 mù xǐ tiáo dá): Trees and most other plants spring out of the earth, shooting upward and outward. They thrive when their growth is uninhibited, and they suffer when they lack adequate water and nutrients and when the earth in which they grow restricts their growth. Hence, wood is said to thrive by orderly reaching.

Morning, east: Morning is the time when the sun rises in the east. In Chinese, east is represented by the character 东 dōng, which was originally 東‍, a pictogram of the sun 日 rì viewed as rising through the trees 木. The rising of the sun corresponds to the upward growth of plants. Wood therefore is therefore associated with the rise and strengthening of yáng qì.

Spring, birth: Spring, which in the yearly cycle corresponds to morning in the daily cycle, is the season associated with wood. This is the time of year when nature springs to life again as many animals give birth, insects appear, trees put forth leaves, and seeds sprout. These activities, which mark the beginning of the yearly cycle of nature, are summed up as birth (生 shēng). The English word spring (springing to life) captures many of the connotations of wood in the five phases.

Green-blue is the color associated with wood. Green is the color that the whole of nature takes on in the springtime. Although nature is green in the summer too, spring is the first appearance of green. So, in the context of the seasons, green can be taken dynamically to connote greening. Of note here is that the Chinese 青 qīng can refer to blue and sometimes black. In translation, we usually render it as green-blue because, in diagnosis, it refers to green and blue colorations of the skin.

Sourness is the flavor associated with wood. Sourness is characteristic of green, unripe fruits and the sap of new growth in the springtime; hence its association with wood.

Wind is the environmental qì associated with wood. Wind is most prevalent in springtime across many parts of China. It shares the stirring qualities of plant and animal life in springtime. As previously noted, the pliability of plants (bending and straightening) is a quality necessary to avoid being destroyed by the wind.

Five-phase cycles: Wood engenders fire, reflecting the way in which wood and vegetation can burn to produce fire. In the restraining cycle, wood restrains earth, referring to the ability of the shoots and roots of plants to break through the earth and to the way wooden tools are used to loosen the earth to ensure adequate drainage of arable land.

The Liver

The Chinese character denoting the liver is 肝 gān, which has an altered flesh radical 肉 on the left, indicating a fleshy body part, and 干 gān/gàn on the right, either simply indicating the sound of the word or offering a pictorial hint of its significance. Gàn 干 means a tree trunk but also denotes many large things, notably including the soldier’s shield. The character may therefore have been constructed to reflect the large brownish-red trunk-like appearance of the liver, with blood vessels appearing to sprout from it as branches. Alternatively, it could reflect the shield-like appearance of the liver. Whether the image is that of a tree trunk or a shield, the liver is ascribed to wood on the basis of a physical analogy, in other words, by magical causality.

The appearance of the organ and especially the use of the metaphor 干 in the graphic representation of its name seem to modern people to be a weak basis for assigning the organ to a particular phase. However, for the Chinese, both appearances and linguistic representations of ideas have always been more significant than they might seem to us, as discussed under magical causality above.

The liver is accorded two main functions: storing blood and free coursing (ensuring the unimpeded flow of qì around the body). It also governs the sinews and the eyes. Of these, the blood-storing function and the relationship to the sinews and eyes rest partially on natural-cause inferences that support the liver’s pairing with wood.

The liver stores the blood: The blood-storing function was undoubtedly inferred from the deep brownish-red hue and bloody texture of the liver, which suggests heavy infusion with blood, and from the knowledge that severe rupturing of the liver as by a weapon usually caused massive hemorrhage swiftly leading to death. Thus, the blood-storing function was inferred from directly observable phenomena, even though such a function is only scantily supported by the findings of modern medical science. It is nevertheless of interest that Europeans once believed that the liver produced the blood, presumably for similar reasons.

The liver’s blood-storing function, like the spirit-storing function of the heart and essence-storing and general storage functions of the kidney, is framed in a container metaphor. However, while a breakdown of the heart’s and the kidney’s storage functions means that what is contained spills out, as in the spirit failing to keep to its abode and insecurity of kidney qì, there is disagreement as to whether the liver’s blood-storing function prevents bleeding. In modern clinical practice, impaired blood storage is usually understood to manifest in reduced amounts of blood, that is, blood vacuity, rather than hemorrhage. In the past, some renowned physicians believed that breakdown of the blood-storing function could result in bleeding.

The liver is the sea of blood: This refers to the blood-storing function. Wáng Bīng’s edited version of the Nèi Jīng states: The liver stores the blood; the heart moves it. When a person moves, blood moves through all the channels; when a person is still, blood returns to the liver viscus. The liver governs the sea of blood for this reason (肝藏血，心行之，人动则血运于诸经，人静则血归于肝脏，肝主血海故也 gān cáng xuè, xīn xíng zhī, rén dòng zé xuè yùn yú zhū jīng, rén jìng zé xuè guī yú gān zàng, gān zhǔ xuè hǎi gù yě). Note that the thoroughfare vessel (冲脉 chōng mài) has also been called the sea of blood.

The liver governs the sinews: The body constituent (tissue) associated with the liver is the sinews, which correspond anatomically to muscles and tendons, overlapping partially with flesh, which is associated with the spleen. Because the sinews enable the body to bend and straighten, they suggest a direct association with wood. In fact, the Chinese word for sinew, 筋 jīn, is itself a metaphor, since it originally denoted the tough but pliable skin of the bamboo utilized in the making of baskets, furniture, and numerous implements. Furthermore, the sinews are directly associated with the liver, since they require copious supplies of blood ensured by the liver’s blood-storing function. Sù Wèn, Chapter 10, states, … when the feet receive blood, one can walk; when the hands receive blood, they can grasp; when the fingers receive blood, they can hold (… 足受血而能步，掌受血而能握，指受血而能摄 zú shòu xuè ér néng bù, zhǎng shòu xuè ér néng wò, zhǐ shòu xuè ér néng shè). The relationship of the blood to the sinews mirrors the relationship of sap to plants.

The liver has its bloom in the nails; the nails are the surplus of the sinews: The health of the liver is reflected in the nails. This notion is derived from direct observation. Insufficiency of the blood, attributed to inadequacy of the liver’s blood-storing function, can be seen in dry nails or pale nails with large moons. The nails are the surplus of the sinews implies that the nails are of a similar but even tougher substance than the sinews. The statement underscores the relationship between the liver and nails.

The liver opens at the eyes: The eyes are associated with liver-wood by analogy and by analytical inference from the blood-storing function.

The eyes are the uppermost sense organ of the body, and since trees grow to a great height, and we go to high places such as mountaintops and treetops to see the lay of the land, a certain physical correspondence between the eyes and the wood phase exists. More importantly, vision is our farthest-reaching sense. When we want to know what is happening in a distant place, we mainly use our eyes, since our other senses do not reach so far. Vision therefore has the quality of reaching outward associated with the wood phase.

Moreover, vision, like the sinews, relies on an adequate supply of blood ensured by the liver’s blood-storing function. Blood vacuity arising when the liver fails to store enough blood is often associated with dry eyes and blurred vision.

Tears are the humor of the liver: Tears are the fluid of the eyes, which serve to keep the eyes clean. They are therefore naturally associated with the liver. Dry eyes are usually a sign of liver yīn vacuity.

The liver governs free coursing: Free coursing as a function of the liver appears not to be derived from any directly observable quality of the organ itself, but rather to be the product of a prospective analogy. In the Nèi Jīng, the term used is 敷和 fū hé, extending harmony. The term free coursing (疏泄 shū xiè, an altered form 踈泄 shū xiè), which in the Nèi Jīng referred to the ability of spleen-earth to drain itself of excess water, was first used by Zhū Dān-Xī (朱丹溪) in the Jīn-Yuán period (13th and 14th centuries CE) to replace and partially reformulate the liver’s function. Yet, whichever term is used to name it, this function of the liver was initially prompted by the orderly reaching quality of wood. Just as wood thrives by orderly reaching, so liver qì thrives when it can course freely around the body. When it is inhibited, the result is that the liver becomes depressed and qì stagnates. Impaired free coursing is one of the main causes of qì stagnation. It manifests in pain, distension, or masses on the liver channel, and a stringlike pulse, such conditions often being associated with emotions such as frustration that results in anger.

The liver governs upbearing and effusion (肝主升发 gān zhǔ shēng fā): The yáng qì of the liver has an upbearing and effusing action, which is analogous to the upward and outward growth of plants. This is the natural movement that ensures the spread of qì to the upper body. It can be affected by anger.

Anger is the mind of the liver: Anger (怒 nù) affects both the free coursing and upbearing effusion of liver qì, which in turn can cause abnormal movement of the blood, which is stored by the liver. For this reason, excessive anger is said to damage the liver. Although the association of emotions with specific organs may seem strange to many modern people, the connection of anger with the liver is easily explained by analytical inferences from direct observation combined with analogy.

We all know that anger causes blood to surge to the head making the face red. This is reflected in our hyperbolic English expression to blow one’s top. In Chinese medicine, when upbearing and effusion of liver qì become excessive, the resulting condition is called ascendant counterflow of liver qì, which can be felt as subjective sensations in the head and upper body. In severe cases, this can in give rise to liver wind, which can result in wind stroke. Anger is not the only factor in these pathomechanisms; yīn-yáng imbalances are the underlying cause. According to biomedicine, anger causes an outpouring of stress hormones like adrenaline, which causes the heart to beat faster and blood pressure to rise, in severe cases giving rise to a cardiovascular event. This occurs in people with hypertension.

Anger is closely related to the frustration we feel when things are not going our way. Chronic anger and frustration can thwart the free coursing action of liver qì, giving rise to qì stagnation. Formulated in this way, things failing to go smoothly is analogous to qì failing to course freely. Not only do anger and frustration impair free coursing, but impaired free coursing due to other causes can also cause susceptibility to anger and frustration, suggesting a strong resonance between the two. The correlation between anger and frustration on the one hand and abnormal movements of qì on the other suggests that the Chinese viewed emotion almost as if it were an aspect of qì.

Shouting is the voice of the liver: Loud speech is required to ensure that one’s voice is heard over a long distance. However, shouting is otherwise associated with anger where the added volume of sound is intended to intimidate. The association of shouting with the liver is therefore probably derived from anger.

The liver is averse to wind: The environmental qì associated with the liver is wind, which has a stirring quality like the growth of plants. Plants bend and sway in the wind, having evolved suppleness to resist wind’s destructive effects. Bodily movement is a product of the sinews, and abnormal movements, such as spasm and tremor, are likened to the effect of wind on plants. Hence, it is said that the liver is averse to wind. Just as plants remain supple when they have enough sap, the sinews need an adequate supply of blood to move freely.

Spasm of various kinds is often associated with blood vacuity arising when the liver fails to keep enough blood in store. Sudden loss of movement, which occurs in stroke patients, can be likened to a violent storm that breaks the branches and trunks of trees. Stroke in English is so named because it is a sudden, violent affliction, and indeed the medical term apoplexy reflects a similar conception. The Chinese used precisely the same metaphor but also added their word for wind. They call stroke wind stroke (中风 zhòng fēng). In this way, wood, the liver’s blood-storing function, and the sinews are all clearly linked together in pathology.

The liver lives/generates life on the left: This is a statement from the Sù Wèn that is little discussed in modern basic theory textbooks. However, it is of interest from the viewpoint of understanding the influence of analogical thinking. When one faces the south, the left side of the body points east, while its right-hand side points west. This reflects an older pairing of the viscera with the five phases based on the position of the viscera within the body), in which the liver was paired with metal, the phase associated with the west (the right side of the body). When the pairing of the viscera with the phases was changed to the modern scheme, the liver became associated with wood and hence the east. The Sù Wèn’s statement that the liver lives on the left seems to represent an effort to bring the function of this organ in line with the five-phase association of wood with the east, despite the contradiction with its anatomical location. The liver lives on the left is contrasted with the lung stores on the right, which is interpreted to mean that although the lung is located on both sides of the chest, its qì descends into the body on the right side, which corresponds to the position west. This issue is discussed in detail in Unschuld and Tessenow’s Huang Di Nei Jing Su Wen, page 741.

The General

The liver holds the Office of General; strategies arise from it. This line, from Chapter 8 of the Sù Wèn, captures many facets of the liver, notably its association with the sinews, the nails, the eyes, and anger.

In the empire paradigm, the army general represents the country’s armed forces, whose mission is to defend the national territory against invasion and to extend its borders outward. The army is to the nation as the sinews are to the body. The nails are the surplus of the sinews, and the word for them in Chinese, 爪 zhuǎ/zhǎo, also means the claws of animals and talons of birds, which are their natural weaponry. Unfortunately, these defensive-offensive associations are lost in the English nail, which refers to a body part exclusively found in humans and other primates, which has all but lost any function as a weapon.

The army needs the brute force of determined fighters to crush enemies, but it also needs an effective intelligence service to map the territory, understand the lay of the land, and perform reconnaissance missions. Hence, the army is to the nation as the eyes are to the body.

Furthermore, the army needs a skilled commander who can predict all the possible enemy operations through time and space and, with a calm mind, evolve effective strategies to counter them. As the Chinese say, the general, in the seclusion of his tent, is able to determine the outcome of distant battles (运筹帷幄之中，决胜千里之外 yùn chóu wéi wò zhī zhōng, jué shèng qiān lǐ zhī wài). By this rationale, the liver was presumed to be the seat of the faculty to devise strategies and to solve problems with a cool head. Hence, the Nèi Jīng says, the liver holds the Office of General; strategies arise from it.

The army is sent into action when it is provoked by an enemy, so anger is also related to the concept of the general, as well as to the physiology of the liver. Anger and brute force are yáng, while intelligent strategizing is yīn. These are complementary tendencies of the liver.

The liver stands in exterior-interior relationship with the gallbladder: The gallbladder is the liver’s corresponding discharging organ. It was recognized to secrete bile, but bile was not understood to have the digestive function as accorded it in biomedicine. Ancient medical scholars described the gallbladder as the bowel of center essence (中精之腑 zhōng jīng zhī fǔ), the bowel of clear cleanness (清净之腑 qīng jìng zhī fǔ), and bowel of center clearness (中清之腑 zhōng qīng zhī fǔ). These epithets suggest that the bile was considered to be a clean and pure internal product rather than a waste product.

The gallbladder holds the Office of Justice; decision arises from it (胆者，中正之官，决断出焉 dǎn zhě, zhōng zhèng zhī guān, jué duàn chū yān). This line suggests that the gallbladder’s function just and balanced decisions. Traditional commentaries suggest that the gallbladder makes decisions for all the bowels and viscera. In particular, the gallbladder’s decision making is a key element to the liver’s function of forming strategies. In such a conception, the gallbladder is the chief adviser to the liver General, curbing the General’s possible tendency to aggression. Decision making implies resoluteness in the execution of decisions. In modern Chinese medicine, breakdown of the gallbladder’s decision-making and resoluteness leads to shyness, timidity, and lack of courage, often referred to as gallbladder timidity. However, according to a different interpretation of 决断 jué duàn, in which 决 jué is taken to mean draining, the gallbladder’s secretion of bile helps the draining function of all the bowels and viscera.

Interestingly, the word gall, for English speakers, has connotations of audacity, even though we now more commonly describe this in metaphors such as nerve or balls. In colloquial Chinese, 胆 dǎn has similar meanings. Audacity is not too distant from the notion of resoluteness associated with the gallbladder in Chinese medicine. Moreover, the liver and gallbladder have been associated with emotions and attitudes (anger, passion, audacity, bitterness, rancor) in different cultures since antiquity, for reasons not entirely clear.

Summary of Liver-Wood

The liver belongs to wood, stores blood, and governs free coursing. It governs the sinews, opens at the eyes, and has its bloom in the nails. Its humor is tears, and its mind is anger. It holds the Office of General.

• The ascription to the wood phase comes from the shape and color of the liver.
• Blood storage is inferred from the color of the liver and from massive hemorrhage following laceration.
• Free coursing and upbearing effusion derive from the association with the orderly reaching quality of wood.
• The sinews and eyes are directly associated with the orderly reaching quality of wood and are dependent on blood storage.
• Anger is associated with disturbances of free coursing and upbearing effusion.
• The liver is averse to wind, as plants in nature are easily damaged by wind when they are not sufficiently supple.
• The army general represents command over the nation’s territory and territorial expansion. The army under his command is the sinew, claws (nails), eyes, and anger of the nation, while he himself is its intelligent strategist.