A system of correspondence like yīn-yáng but operating on the basis of five categories. The five phases are symbolized by the terms wood, fire, earth, metal, and water.

Five Phases in Cosmology (五行在宇宙学中的应用 wǔ xíng zì yǔ zhōu xué zhōng de yìng yòng)

The correlative thinking that gave rise to yīn-yáng theory also produced the theory of the five phases, a further theoretical cornerstone of Chinese medicine. The five phases wood, fire, earth, metal, and water are categories used for classifying things and phenomena that are similar in nature and exhibit similar relationships. They five-phase system is therefore similar to yīn and yáng, except that it has five categories instead of two.

This organizational and explanatory scheme was applied to any objects or phenomena that played an important role in human life, associating them each with the cycle of seasons and the activities of man and nature that occurred in them. Already in early China, numerous groups of five were identified with the natural symbols wood, fire, earth, metal, and water.

Origins

The concept of the five phases developed from the notion of five things―wood, fire, earth, metal, water―considered important for human life. These were originally called the five cardinal things (五方 wǔ fāng) or the five materials (五才, 五材 wǔ cái). Earth was important for providing food; wood and metal were important for the making of shelter and artefacts; water and fire were primarily important for the preparation of food and the production of metals.

As natural philosophers focused their attention on affinities between the disparate phenomena of the universe, they lighted on the idea that the five materials possessed qualities that could provide a framework for general categorization of things. The basis for a leap forward was provided when the five materials were paired with the seasons.

Basic Features (五行的基本特点 wǔ xíng de jī-běn tè-diǎn)

Five-Phase Categorization

Each phase is primarily associated with one of the five seasons, spring, summer, late summer (the latter part of the summer), autumn, and winter, according to the type of activity occurring in nature at the time. Wood is associated with spring and birth; fire with summer and growth; earth with late summer with transformation; autumn with withdrawal, and winter with storing. Many other associations, especially those applicable in medicine, are derived from these primary correspondences.

• Time of day: The seasons of the annual cycle of nature are correlated with times of the day in the diurnal cycle. Thus, dawn corresponds to spring (wood), noon to summer (fire), afternoon to late summer (earth), sunset to autumn (metal), and winter to night (water).
• Position: The position of the sun at each time of the day allows the positions north, south, east, and west to be likewise correlated to the phases.
• Weather: Each phase is associated with a distinct type of weather (based on the climate of China and not necessarily universal): wood with wind; fire with summerheat; earth with damp-ness; metal with dryness; and winter with cold.

  Color and flavor: The phases are each associated with a color and flavor: wood with green-blue and sourness; fire with red and bitterness; earth with yellow and sweetness; metal with white and acridity; water with black and saltiness.

Of course, many other items are classified according to the five phases, including grains, domestic animals, musical notes, and smells. However, these have little or no significance in medicine.

The characteristics of the five phases and the rationale for associating numerous disparate phenomena with them is a complex issue, which is discussed at length in Chinese Medicine: The Ideas that Shaped It, Chapter 3 (3.8.1).

The essential characteristics of each phase are as follows:

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 the 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 or when the earth in which they grow restricts their growth. Hence, wood is said to thrive by orderly reaching.

Spring, birth: Spring 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.

Morning, east: Spring in the yearly cycle corresponds to dawn and morning in the daily cycle, when the sun rises in the east, represented by the character 东 dōng in Chinese, which was originally 東, a pictogram of the sun 日 rì viewed as rising through the trees 木.

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 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 necessary quality for them to avoid being destroyed by the wind. Hence, a natural connection exists between wind and wood.

Fire

Though fire is a powerfully destructive force, it is an equally powerful benefit when harnessed. The mastery of fire was an accomplishment that had long-term consequences for human evolution, enabling humankind to inhabit virtually every part of the globe and develop technology. It provided warmth that enabled us to live in cold climes. It provided protection against predators, especially at night. By providing light, it enabled us to extend daytime activities and reduce sleeping time, which eventually changed our circadian rhythms.

The fire is the heart of the human community. Keeping a fire going required social interaction. Activities performed around the fire at night deepened family and social ties. Still to this day, a campfire symbolizes warmth, safety, and social conviviality.

The cooking of food made possible by fire had numerous benefits: reducing harmful bacteria and parasites, removing toxins, making food more easily digestible, and facilitating preservation. Switching to cooked food increased the range of edible foods and caused our teeth and intestines to adapt to softer foods. Cooked food destroys certain nutrients but makes others more available. It accentuates flavors and enables them to be combined, encouraging the development of food preparation as an art form.

Early humans learned to use fire to harden wood to make specialized tools, to burn vegetation to prepare the land for farming, and by controlled burning to nourish the earth by the nutrients from ash. Without fire, we would never have learned how to smelt ores to produce metal or cauterize wounds to prevent infection. Indeed, the whole of human technological progress would have been impossible without fire. Some evolutionary biologists have even argued that the development of our current brain size and speech would not have occurred without harnessing fire.

Not surprisingly, therefore, fire has great symbolical value in all cultures, representing warmth, power, conviviality, and splendor, as well as the negative connotation of destruction and torment. Light, closely associated with fire, enables us to see and understand the world, and so is a symbol of consciousness, intelligence, and perspicacity.

Many cultures use fire ceremoniously to carry things to the spirit world or otherwise communicate with it. In Chinese culture still to this day, sheets of paper symbolizing money and sometimes even items of clothing are burnt to provide for the needs of the dead. Incense is burned for religious purposes throughout the major civilizations of the Eurasian continent. A plausible explanation for these practices is that when something burns, its physical form is destroyed, and it gives off smoke that rises upward, just as the body after death is believed to decompose and release the spirit dwelling within. Rising smoke therefore symbolizes transcendence to the spirit world. In the Zhōu dynasty, orders for the destruction of illness-causing demons were implemented by burning the paper on which their names were written.

Of course, fire has also been used medically in China in the burning of mugwort, which warms the body, helps the flow of qì, and eliminates evils. It is also widely used in the processing of medicinals.

Fire is the flaming upward (火曰炎上 huǒ yuē yán shàng): In Chinese medicine, fire is classically said to have the quality of flaming upward, that is, heat and upward movement. It is the most yáng of all the phases.

Summer, growth: Summer is the season when the sun reaches its highest point and provides the greatest heat in the yearly cycle. Even though the ancients did not know that the sun was, in fact, a gigantic thermonuclear reaction, they realized by analogical reasoning that it shared the yáng qualities of fire. The Chinese refer to the sun as 太阳 tài yáng, the supreme yáng, reflecting the notion that it is the essence of yáng (阳之精 yáng zhī jīng).

Growth is the activity associated with summer. Although growth begins in springtime, it accelerates greatly as a temperature rises in the early summer.

Noon, south: South is the position of the sun when it is highest in the sky at noon in the daily cycle. Hence, noon corresponds to summer in the yearly cycle.

Red is the color associated with fire for several reasons. Red is seen in flames and in glowing embers. It is also associated with the sun, especially at sunset. The warmth of the sun in the summer turns fruits red. Although fruits are also red in late summer, summertime represents the first appearance of red.

Bitterness is the flavor associated with wood because burnt food tastes bitter. Note that although red fruits are sweet, sweetness is associated with earth, not with fire, because it is in late summer that fruits develop their maximum sweetness.

Earth

All the food we eat comes directly from crops grown in the earth or from animals feeding on vegetation growing from the earth. Hence, earth is the mother of the myriad living things (万物之母 wàn wù zhī mǔ), things here referring to all forms of life. Salt, our main mineral food additive, comes from the earth too.

Late summer, transformation: The Chinese, as we do, normally speak of four seasons, not five. However, with the development of the five-phase doctrine, the year had to be divided into five. For this reason, late summer (长夏 cháng xià) was inserted between summer and autumn, the turning point between yáng and yīn parts of the year. This time was chosen because it is a time very important in human agriculture when staple crops ripen and become edible. The activity of nature at this time is summed up as transformation (化 huà).

The exact definition of this season is the subject of disagreement, but Wáng Bīng, the renowned commentator of the Nèi Jīng, said that it is the last month of summer, the sixth month of the lunar calendar, corresponding to the end of July and beginning of August in our calendar.

Afternoon, center: Afternoon is the part of the day that corresponds to late summer in the yearly cycle.

The earth phase is also associated with the central position. Unlike the positions of the other four phases, the center is not related to the position of the sun. It is the position associated with the ruler, so the earth-center pairing probably arose when the heart, rather than the spleen, was associated with earth in an earlier pairing of the viscera to the phases.

Earth is the sowing and reaping (土爰稼穑 tǔ yuán jià sè): Although sowing and reaping are two separate activities, neither of which is associated with late summer, the combination of the two simply means the work of producing food out of the earth, that is, agriculture.

Yellow is the color associated with earth. The Chinese 黄 huáng covers a wider range of colors than the English yellow, notably including light brown. Brown-haired dogs, tan-colored shoes, and normal-colored feces are described as 黄. So, yellow is the color of earth, especially the earth in the Yellow River region, which is paler than the deep brown of other climes. It is also the color of staple crops as they ripen. Although yellow is the color of grasses in other seasons of the year, late summer is the coming of yellow.

Sweetness is the flavor of grains and fruits as they become ready for harvesting. Sweet foods build qì and blood, and in fact, sweetness is a common property of all supplementing medicinals.

Metal

Metal as a material refers to any kind of metal, but notably the hardest of metals known to early medical scholars, iron.

Metal is the working of change (金曰从革 jīn yuē cóng gé). The Chinese 革 gé originally signified the process of removing hair from animal hides to make leather and later denoted change in general. Being hard, sharpenable, heat resistant at the burning point of wood, malleable when red hot, and moldable when superheat forces it into a liquid state, metal is the most versatile of materials for making all manner of tools, utensils, and instruments, such as knives, scythes, axes, hoes, spades, and numerous weapons, as well as pots, pans, pipes, and bells. It is especially associated with blades used to harvest grains, slaughter animals, and kill enemies.

Metal comes from ores dug out of the earth. Ore is smelted at high temperature to release the metal from the other minerals. The best metals are those that are freest of impurities, and so the concept of metal is closely associated with purity.

Autumn, withdrawal: Autumn is the time when frost causes trees to lose their leaves and when grasses and insects die, in other words, the time when nature withdraws into itself. The destructive action of frosts and cold weather on nature can be naturally likened to a knife. This notion of autumn is captured in the expression 肃杀 sù shā, purification and killing or ruthless purification, in which 肃 connotes the harsh purging quality of the bleak cold and stillness of autumn, and 杀 means to kill. Autumn is also a time when humans harvest their crops and slaughter animals to provide stores of food for the winter. Harvesting and slaughter require the use of metal scythes and knives. In Chinese, these ideas are summed up in the abstract concept of 收 shōu, which means both withdrawal (of nature) and gathering (of winter supplies). Thus, the association between metal and autumn revolves around the working of change, purification, the withdrawal of nature, and the gathering of sustenance.

West, sunset: Corresponding to autumn in the daily cycle is evening, when nature rests and humans cease their toil and withdraw to their homes. Since the sun sets in the West, the westerly position is also associated with metal.

Dryness is the environmental qì associated with metal because metal is unable to absorb water and hence is totally dry. Dryness prevails in many parts of China in the autumn. It is closely associated with cleanliness and purity. The modern Chinese word for clean is 干净 gān jìng, literally meaning dry [and] clean.

White is the color associated with metal. The color white corresponds to autumn, the time when the white frost comes. Although white could also be associated with the snow of winter, autumn marks the arrival of whiteness in nature. White is particularly associated with the west since the western mountains of China are snow-clad for much of the year. White is also the color of clothing worn at Chinese funerals to this day. It is the color that symbolizes grief and sorrow, presumably by association with the frosts to which nature succumbs in the fall.

Acridity, also called pungency, is associated with metal because iron gives off a sharp, acrid smell during the smelting process.

Water

Water is vital to life. Even our bodies are nearly 70% water. We can only survive for a couple of days without this precious substance.

Water also has the quality of cold. Even in summer, it tends to remain cool. This is because, as modern science tells us, water has a high specific heat capacity, which means a lot of heat is needed to warm it up. Therefore, in summer the ocean takes longer to heat than the land.

Water moistens and descends (水曰润下 shuǐ yuē rùn xià): The water phase is classically described as having the qualities of moistening and descending. Moistening reflects the water’s life-nurturing effects. Descending refers to the fact that it descends to low places, gravitates to low ground, where it finally becomes still.

Winter, storage: Since cold, stillness, and nurturing are all yīn qualities, the water phase is associated with winter, the coldest season, when activity in nature, as symbolized by yáng qì, reaches its lowest ebb and many life forms are reduced to inactive forms. In winter, water reaches its lowest temperature and turns to ice, finding its ultimate and total stillness. Animals are in hibernation, deciduous trees are leafless, and many plants survive only in seed or root form. Winter therefore has the qualities of dormancy or latency, which, again, are yīn qualities. These qualities are summarized in the concept of 藏 cáng, which means storing or hiding. Winter storage is the deepest and quietest form of nurturing. The nurturing quality of winter is something that farmers are very much aware of. They know that a good harvest follows a cold snowy winter (瑞雪兆丰年 ruì xuě zhào fēng nián).

North, night: North is the position of the sun when it is lowest in the sky and provides the earth with the least light and heat. Northern places are darker and colder than southern places. Winter is the season when the sun hides for much of the time in northern climes.

Nighttime is the part of the daily cycle that corresponds to winter in the yearly cycle by the absence of sunlight.

Black is the color associated with the water phase. The color black is associated with water possibly because of the lack of sunlight in winter and the blackish appearance of water in winter landscapes. One might well have expected white to be the color corresponding to winter, given that it is the season of snow. However, color associations seem to be based on the season in which a color first appears, which, in the case of white, is autumn.

Saltiness is the flavor associated with water: When water in the environment reaches the ocean, it becomes salty. Salt leaches water out of things. Hence, it works as a preservative for vegetables and meats, enabling them to be stored for the winter when fresh foods are scarce. Furthermore, empirical evidence taught that certain salty medicinals act on the kidney, the viscus associated with the water phase.

Five-Phase Cycles

Engendering, Restraining, Overwhelming, Rebellion

Not merely categories for classifying things by their nature, the five phases have interrelationships, which take the form of four cyclical developments. These are called thefive-phase cycles. Two of these, namely the engendering cycle and the restraining cycle, reflect normal, healthy interaction between phenomena. The other two, namely overwhelming and rebellion, reflect abnormal or unhealthy interactions.

Engendering: The engendering cycle (相生 xiāng shēng) is the cycle in which a thing or phenomenon belonging to one phase gives rise to or gives way to the corresponding thing or phenomenon belonging to another phase, as follows:

• Wood engenders fire because it burns to produce fire.
• Fire engenders earth since it creates ashes, which return to the earth.
• Earth engenders metal since the ores found in the ground represent concentrations of earth.
• Metal engenders water since, when heated, it turns to liquid. An alternate explanation states that it encourages condensation in the presence of cold.
• Water engenders wood for the obvious reason that plants grow when watered.

The engendering cycle is reflected in the sequence of the seasons. Spring (wood) gives way to summer (fire), which gives way to late summer (earth), which in turn gives way to autumn (metal), which again gives way to winter (water).

In the diagram, the outer arrows indicate the engendering cycle.

A phase that engenders another is called the engendering phase (生我 shēng wǒ), while the phase that is engendered by another is called the engendered phase (我生 wǒ shēng). Following the Nàn Jīng, the phases are often labeled as mother and child. The engendering phase is called the mother (母 mǔ), while the engendered phase is called the child (子 zǐ).

Restraining: The restraining cycle (相克 xiāng kè), also called the overcoming cycle, is the cycle by which each phase keeps the other in check. The phase that each phase restrains is the next-but-one in the engendering cycle. In terms of mother and child, this means that a phase restrains the child of its child, and each phase is restrained by its mother’s mother. The restraining relationships are described in the following way:

In the diagram, the internal arrows indicate the restraining cycle.

• Earth dams water.
• Water douses fire.
• Fire melts metal.
• Metal fells wood.
• Wood loosens earth. (Early agricultural implements were made of wood.)

The phase that restrains another is called the restraining phase (克我 kè wǒ) or the overcoming phase (所胜 suǒ shèng). The phase that is restrained by another is called the restrained phase (我克 wǒ kè) or the overcome phase (所不胜 suǒ bù shèng).

Overwhelming: The overwhelming cycle (相乘 xiāng chéng) is an exaggeration of the restraining cycle, in which one of the phases becomes weaker and allows the phase that normally restrains it to invade and weaken it further.

Rebellion: The rebellion cycle (相侮 xiāng wǔ) is the restraining cycle in reverse. It comes into play when a phase becomes relatively stronger than the phase that would normally restrain it.

Five Phases in Medicine

Early Chinese physicians applied five-phase theory to medicine in various ways. The most important of these was the establishment of correspondences between the five viscera and the five phases. The five phases were instrumental in the formation of theories concerning the functions of the viscera and their interrelationships, as well as in the development of treatment strategies.

Five Phases in Anatomy and Physiology (用五行阐释人体的解剖和生理功能 yòng wǔ xíng chǎn shì rén tǐ jiě pōu hé shēng lǐ gōng néng)

Each of the viscera is associated with a phase. The liver is associated with wood, the heart with fire, the spleen with earth, the lung with metal, and the kidney with water. In the context of five-phase discussions, the viscera are often referred to as liver-wood, heart-fire, spleen-earth, lung-metal, and kidney-water. Note here that heart-fire is different from heart fire, which is pathological fire in the heart.

Influence of Five-Phase Theory in Physiology

The application of five-phase theory in physiology had a great influence over the understanding of the internal organs.

Multiple sets of five: A major product of the influence of five-phase theory is the physiological model of Chinese medicine that centers around five internal organs, each of which has special relationships to body parts and other groups of five. Each viscus is associated with one of the five body constituents, five orifices, the five humors, the five minds (emotional or mental states), five voices, as well as the five flavors and the five colors.

Functions influenced by the five phases: While many functions of the bowels and viscera are derived from their shape or their movements, others were derived by the application of five-phase theory. For example, while ancient physicians were able to identify the urinary function of the kidney by anatomical observation, the further attribution of the essence-storing function to the kidney was probably prompted by the notion of storage associated with the water phase. While the blood-storing function of liver may have been deduced from its deep-red color, the attribution to the liver of free coursing, described by analogy to wood’s liking of orderly reaching, was clearly influenced by five-phase theory.

Cyclic Interactions

The five phases can inform our understanding of relationships between individual items that correspond to each other in a five-phase relationship, such as relationships between the five viscera or between the five minds. These are primarily informed by the cycles of engendering and restraining.

Engendering: Liver-wood engenders (has a nurturing effect on) heart-fire; heart-fire engenders spleen-earth; spleen-earth engenders lung-metal; lung-metal engenders kidney-water; and kidney-water engenders liver-wood. In practice, this is reflected in the following observations:

• Liver-wood’s free coursing benefits the heart’s propulsion of the blood.
• Heart-fire’s propulsion of the blood is beneficial to the spleen.
• Spleen-earth’s movement and transformation of the essence of grain and water is beneficial to the lung’s function of governing qì.
• The lung’s depurative downbearing function is beneficial to the kidney’s functions of governing water and absorbing qì.
• Essence stored by the kidney nourishes the liver’s yīn blood.

Restraining: The restraining cycle is liver-wood restrains spleen-earth, which in turn restrains kidney-water, which restrains heart-fire, which restrains lung-metal, which restrains liver-wood. This is reflected in the following observations:

• Liver-wood’s free coursing action prevents spleen qì from congesting, thereby enhancing its movement and transformation function.
• Spleen-earth’s movement and transformation function normally helps prevent kidney water from flooding.
• Kidney yīn restrains heart yáng so that it prevents heart fire from getting out of control.
• Heart-fire’s yáng qì restrains the diffusion and downbearing functions of the lung, maintaining the lung’s function of governing qì.
• Lung-metal’s depurative downbearing function can help to restrain ascendant hyperactivity of liver yáng.

Five Phases in Pathology (用五行阐释人体的病理变化 yòng wǔ xing chǎn shì ren tǐ de bìng lǐ biàn huà)

Disease shifts among the viscera can be explained by the laws of mother and child affecting each other, which are abnormalities of the engendering cycle, and by the overwhelming and rebellion cycles, which are both abnormalities of the restraining cycle.

Note that an understanding of disease patterns of the viscera is required for easy reading of what follows here.

Mother and Child Affecting Each Other

Mother and child refer to phases in the engendering cycle. For example, water engenders wood, so water is the mother of wood, and wood is the child of water. When disease passes from one viscus to the viscus that it engenders, as when liver-wood disease passes to heart-fire or heart-fire disease passes to the spleen-earth, this is called disease of the mother affecting the child (母病及子 mǔ bìng ji2 zǐ) or vacuous mother affecting the child (母虚累子 mǔ xu1 leì zǐ). The classic example of disease of the mother affecting disease of the child is water failing to moisten wood (水不涵木 shuǐ bu4 han2 mu4), which means kidney yīn failing to keep liver yīn sufficient. This manifests in kidney signs such as vexing heat in the five hearts, tinnitus, deafness, aching lumbus, seminal emission and dry throat, together with kidney signs such as dizziness, headache, and visual disturbances such as dry eyes or night blindness.

Conversely, when disease spreads from a given viscus to the viscus by which it is engendered, this is called disease of the child affecting the mother (子病及母 zǐ bìng ji2 mǔ), the child stealing the mother’s qì (子盗母气 zǐ dao4 mǔ qì), or disease of the child invading the mother (子病犯母 zǐ bìng fàn mǔ). The classic example of this is when liver-wood disease affects kidney-water, giving rise to aching lumbus and knees, dizzy head, tinnitus, and seminal emission or menstrual irregularities.

Overwhelming and Rebellion Cycles

Overwhelming and rebellion are both abnormalities of the restraining cycle (wood → earth → water → fire → metal → wood). Both can arise in two ways.

Overwhelming (相乘 xiang1 chéng) is excessive restraining. It can be the result of an excessively strong restraining phase or an excessively weak restrained phase. For example, liver-wood often overwhelms spleen-earth. This can be the result of effulgent wood overwhelming earth (木旺乘土 mu4 wang4 chéng tǔ) or vacuous earth allowing wood to overwhelm it (土虚木乘 tǔ xu1 mu4 chéng).

Rebellion (相侮 xiang1 wǔ) is the restraining cycle in reverse. Wood rebels against metal, metal rebels against fire, fire rebels against water, water rebels against earth, earth rebels against wood. Again, it can arise in either two ways: either the phase that is supposed to be restrained by another becomes stronger than the other, or the phase that is supposed to restrain becomes weaker than the other. Put more simply, a restrained phase becomes excessively strong, or a restraining phase becomes excessively weak.

Let us take the example of wood rebelling against metal. When liver fire (heat) invades the lung, this is a situation of wood rebelling against metal that arises when the restrained phase (wood) becomes stronger than the restraining phase (metal). This is often called wood fire tormenting metal (木火刑金 mu4 huo3 xíng jīn). Lung vacuity allowing the liver to rebel is a case of wood rebelling against metal that arises when the restraining phase grows weak.

Five Phases in Diagnostics (五行在诊断疾病的应用 wǔ xíng zaì zhen3 huà ji2 bìng de yìng yòng)

Five-phase theory is applied in diagnosis in several different ways. The following schemes are now largely understood to be theoretical and are not generally applied in modern clinical practice.

Color of Complexion, Flavor, and Pulse as Indicators of Disease Locus

Each of the five phases is associated with a specific complexion, taste in the mouth, and pulse, indicating disease of the corresponding viscus.

• Disease of liver-wood: green-blue complexion; sour taste in the mouth; stringlike pulse.
• Disease of heart-fire: red complexion; bitter taste in the mouth; surging pulse.
• Disease of spleen-earth: yellow complexion; sweet taste in the mouth; moderate pulse.
• Disease of lung-metal: white complexion; acrid taste in the mouth; floating pulse.
• Disease of kidney-water: black facial complexion; salty taste in the mouth; sunken pulse.

This is an ancient theoretical scheme that is now no longer believed to have complete clinical validity. In clinical practice, the correspondence of complexions is far more complex, and it is doubtful whether it is possible to distinguish five tastes in the mouth.

Color of Complexion as Indication of Disease Shifts

Incongruence between the phase associated with the color of the complexion and the phase associated with the signs of disease can indicate the passage of disease from one viscus to another. Below are some examples.

• In spleen disease with poor appetite, abdominal distension, abdominal pain, sloppy stool or diarrhea, the facial complexion should be yellow (withered-yellow). If it is green-blue instead, this indicates wood overwhelming earth.
• In lung disease characterized by cough or panting, the appearance of a red complexion and surging pulse indicates heart disease passing to the lung, which is fire overwhelming metal.
• In heart disease marked by palpitation, insomnia, and heart vexation, the appearance of a blackish complexion may indicate kidney disease passing to the heart, which is water overwhelming fire.
• In liver disease, the appearance of a white complexion may indicate lung disease passing to the liver, which is metal overwhelming wood.
• In kidney disease, the appearance of a yellow complexion may indicate spleen disease passing to the kidney, which is earth overwhelming water.

Prognosis Based on Congruence and Incongruence of Color and Pulse

A diagnostic practice described in the Líng Shu1 (Magic Pivot) determines prognosis on the basis of the five-phase congruence or incongruence of the color and pulse. For example, when in liver disease the complexion is green-blue and the pulse is stringlike, color and complexion both correspond to the wood phase and hence are congruent. In such cases the prognosis is good. If, by contrast, the pulse is floating instead of stringlike, it corresponds to metal, the phase which restrains wood (or overwhelms wood). In such cases, the prognosis is poor. If, on the other hand, the pulse is the sunken pulse of kidney-water, the color and pulse are again incongruent. However, because the pulse belongs to water, the phase that engenders wood, the prognosis is favorable.

Five Phases in Treatment (五行在治疗原则的应用 wǔ xíng zài zhì liáo yuán zé de yìng yòng)

Principles and Methods of Treatment Based on Engendering

The principle of supplementing insufficiency and draining superabundance entails directly supplementing and draining an affected viscus. Extensions of this are the principles of treating vacuity by supplementing the mother and treating repletion by draining the child, which are based on the engendering cycle of the five phases. This approach to treatment is sometimes applied systematically in acupuncture, but in medicinal therapy it is only applied in specific cases.

In vacuity, supplement the mother (虚则补其母 xū zé bǔ qí mǔ): This involves applying a supplementing stimulus to the viscus that engenders the affected viscus. For example, kidney-water engenders liver-wood, so liver vacuity can be treated by supplementing the kidney.

In repletion, drain the child (实则泻其子 shí zé xiè qí zǐ): This entails applying a draining stimulus to the viscus that the affected viscus engenders. For example, liver-wood engenders heart-fire. So, when liver fire is exuberant, giving rise to upper body signs, it can be treated by draining the heart.

In vacuity, supplement the mother; in repletion supplement the child can be applied to disease of the mother affecting the child or the child stealing the mother’s qì. Disease of the mother affecting the child is disease spreading from one viscus to the viscus it engenders in the five phases. One example is ascendant hyperactivity of liver yáng giving rise to exuberant heart fire; another is spleen-stomach vacuity giving rise to insufficiency of lung qì. The child stealing the mother’s qì is vacuity in one viscus gives rise to vacuity in the viscus engendering it, as when lung qì vacuity gives rise to spleen vacuity with impaired movement and transformation.

In vacuity, supplement the mother; in repletion supplement the child can also be used for simple cases of disease of the child that has persisted for a long time.

When supplementing the mother, the child is often supplemented too.

Applications in acupuncture: The principle of treating vacuity by supplementing the mother can be applied by supplementing points on the channel belonging to the phase that engenders the channel affected by vacuity. For example, water engenders wood, so vacuity in the channel belonging to liver-wood can be treated by applying a supplementing stimulus to points on the channel that belongs to kidney-water.

In the same way, the principle of treating repletion by draining the child is applied by draining a channel engendered by the one affected by repletion. For example, wood engenders fire, so liver fire can be treated by draining points on the heart channel.

In addition, the five transportation points, a group of points located on each of the twelve main channels, each have five-phase associations. These are selected according to rules derived from the engendering and restraining cycles.

Nevertheless, it should be noted that many styles of acumoxatherapy have developed over the centuries, not all of which apply these principles.

Applications in medicinal therapy: The principle of treating vacuity by supplementing the mother and treating repletion by draining the child finds expression in specific methods of treatment in medicinal therapy.

Supplementing the mother.

• Enriching water to moisten wood (滋水涵木 zī shuǐ hán mù): Also called enriching the liver and kidney (滋补肾肝 zī bǔ gān shèn). This is supplementing kidney yīn to nourish liver yīn in the treatment of water failing to moisten wood (水不涵木 shuǐ bù hán mù), i.e., kidney yīn depletion giving rise to insufficiency of liver yīn, in turn allowing the development of hyperactivity of liver yáng, characterized by dizzy head and vision, tinnitus, reddening of the cheeks, dry mouth, vexing heat in the five hearts, limp aching lumbus and limbs, red tongue with scant fur, and a pulse that is fine, stringlike, and rapid.
• Banking up earth to engender metal (培土生金 péi tǔ shēng jīn): Also called supplementing the spleen and lung (补养脾肺 bǔ yǎng pí fèi). This method involves supplementing the spleen and boosting qì while simultaneously supplementing lung qì. It treats vacuous spleen-stomach failing to nourish the lung, giving rise to spleen-lung vacuity, which is characterized by enduring cough with copious clear thin phlegm or scant sticky phlegm with reduced eating, sloppy stool, lack of strength in the limbs, and a pale tongue and weak pulse.
• Mutual engendering of metal and water (金水相生 jīn shuǐ xiāng shēng): Supplementing both the lung and kidney to treat lung-kidney yīn vacuity. It is based on the principle that metal can engender water and water can moisten metal. It is applied when the lung is vacuous and cannot distribute fluid to enrich the kidney or when kidney yīn is insufficient and its essential qì cannot ascend to enrich the lung. In either case, the signs are cough, dry cough or coughing of blood, hoarse voice, tidal heat effusion, dry mouth, night sweating, seminal emission, and aching lumbus and weak legs, emaciation, a red tongue with scant fur, and a pulse that is fine and rapid.
• Boosting fire to supplement earth (益火补土 yì huǒ bǔ tǔ): Warming and invigorating kidney yáng to supplement spleen yáng. This method is used to treat depletion of kidney yáng causing devitalized spleen yáng. Although in the term boosting fire to supplement earth the word fire originally referred to the heart, it was redefined as kidney yáng when the life gate fire came to be defined as kidney yáng.