You are here

Understanding Yin and Yang

by Tony Reid

One of the key theoretical foundations of traditional Chinese medicine (TCM) is the twin concept of Yin and Yang. The ancient Chinese philosophers used ‘Yin’ and’Yang’ to explain the changes that occur in nature. All things and phenomena in the universe contain two opposite aspects (Yin and Yang) which are, at the same time both interdependent and in conflict. These opposite principles are complementary to one another, yet may also be in opposition to each other.

According to the Su Wen:

“Yin-Yang is the way of heaven and earth, the guiding alignment of all matters, the parentage of all change, the origin of birth and death.” The ancients Chinese observed these principles in the natural events around them: day and night, light and darkness, growth and decay, activity and rest, summer and winter, man and woman, hot and cold, heaven and earth, sun and moon, etc.

They noticed two important features of the relationships between opposites:

  1. There is some sort of correlation between the individual components of different pairs of opposites. In other words there is an essential quality that is common to one partner in each pair. This quality was designated as either Yin or Yang. During the day it is light and warm, the sun is out and people are active. These particular components – daytime, light, warmth, activity and the sun – all share an essential quality. This quality is referred to as Yang. The nearest concepts in Western thought are:‘active’, ‘positive’ and ‘expansive’. On the other hand there is night-time, darkness, cold, rest and the moon, all of which share in an essential quality that is opposite in nature. This quality is referred to as Yin, which approximates a combination of the concepts of ‘latent’, ‘reactive’, ‘responsive’ and ‘contracted’. 
  2. One component in a pair of opposites has certain distinctive relationships with the other component. Day changes into night, and night into day; the longer the day, the shorter the night and vice versa; summer changes to winter and winter into summer; activity is followed by rest, rest supports activity; dormancy is followed by growth which is followed by decay. In all areas of life these relationships describe the natural laws behind the continuous change, the orderly development, the rise and the fall that can be observed in nature and in human affairs.

The Chinese characters for Yin and Yang depict the sun shining on a hill: Yin denotes the shade side and Yang denotes the sunny side.

Yin-Yang Classification

Yin is related to darkness, shadow, latency, reaction, response, decline, quietness, cold, and softness. Yang is related to light, brightness, activity, growth, loudness, heat and hardness. The Chinese characters for Yin and Yang depict the sun shining on a hill: Yin denotes the shade side and Yang denotes the sunny side.

                                                   YIN                                                                             YANG

Position:                  below, lower, ventral, interior                                                above, upper, dorsal, exterior

Temperature:                             cold                                                                                hot

Motion:                    passive, slow, underactive, irregular                                      active, fast, overactive, regular  

Illumination:                             dark                                                                               bright

Direction:                             descending                                                                       ascending

Demeanor:                        dull, apathetic, gloomy                                               alert, involved, outgoing

Emotions:                         sadness, grief, calm                                          excitement, happiness, enthusiasm

Human Being:                       physical body                                                                     spirit

Organs:                          solid organs (e.g. Heart)                                              hollow organs (e.g. Stomach)

Aspect of an organ:                substance                                                                functional activity

Disorder:                       degenerative, organic disease                                           functional disorders

Stage of disease: chronic, regressing, degenerating                                                acute, progressing

Disease:                             pathogenic factors                                                         host resistance

Pathogenic factors: Cold, Damp, stagnant Qi, static Blood, Phlegm, Fluid            Heat, Wind, Dryness, Heat Toxin

Disease type:                             interior, cold, deficiency                                         exterior, hot, excess

Injured by excessive:                       Walking                                                                  Staring

Pulse quality:                        deep, weak, slow, soft                                   floating, forceful, rapid, hard (‘wiry’, ‘tight’, ‘taut’)

It is important to note that Yin and Yang do not refer specifically to any concrete object or phenomenon.They are used as tools to observe and analyse things and events in order to indicate a tendency or an inherent quality. This tendency or quality is also relative and exists only in comparison to something else. For example, if we take the climate in England and compare it with the climate in the tropics, then we can say that in general, the English climate is colder, and therefore Yin in comparison with the climate in the tropics which is warmer and therefore more Yang. However, if we compare England’s climate to that of the North Pole, then the English climate is Yang by comparison. The Chinese philosophy of Yin-Yang points to the underlying unity of opposites, their interdependence, and transformation of one into the other.

The relationships between opposites

There is always some kind of relationship that exists between opposites, and this leads to the crucial difference between Chinese and Western philosophy. In the West, opposites are regarded as separate, static and always exclusive. This has molded our worldview and continues to dominate scientific thinking. On the other hand, the Chinese philosophy of Yin-Yang points to the underlying unity of opposites, their interdependence, and transformation of one into the other. It provides a viewpoint from which the complementary nature of opposing pairs can be observed and utilized in practice.

These relationships have five essential aspects:

1. Yin and Yang oppose each other.

Day and night have different effects on living beings, i.e. most creatures sleep at night and are active during the day. In addition the qualities of day and night are opposite in nature (day: light, warmer; night: darkness, colder).

2. Yin and Yang are interdependent.

Day and night are interdependent in the sense that the one gives definition to the other; the qualities of the one are defined with reference to those of the other, e.g. light is the absence of darkness; darkness is the absence of light.

3. Yin and Yang consume one another.

When the sun rises and the day begins, day has totally replaced night, and vice versa. This is most apparent at dawn and dusk, as the encroaching sunlight subsumes the darkness at dawn and the encroaching darkness banishes the light of the sun at dusk.

4. Yang and Yang changes into Yin.

In the course of the 24 hour diurnal cycle, day changes into night and night into day.

5. Yin and Yang are infinitely divisible.

As discussed above, the daytime (Yang) has morning (Yang) and afternoon (Yin); while the nighttime (Yin) has the period before midnight (Yin) and the period after midnight (Yang).

Yin-Yang in TCM

The whole science and art of traditional Chinese medicine – its physiology, pathology, diagnosis and treatment – is based upon Yin-Yang, and every aspect can be understood and expressed in terms of Yin and Yang.

TCM Physiology

The Qi is Yang and the Blood is Yin. 

The solid organs (viscera) are Yin, and the hollow organs (bowels) are Yang.

The upper body is Yang and the lower body is Yin.

The exterior of the body is Yang, and the interior is Yin.

Functional activities are Yang, structure and nutrient substances are Yin.

Conservation, storage, physical structure and substances are Yin.

Transformation, change, movement and activity are Yang.

TCM Pathology

Excess conditions are Yang, and deficiency conditions are Yin.

Pathogenic factors that come from outside of the body are Yang. Pathogenic factors that are generated within the body are Yin.

In general, pathological changes that occur during disease may be explained as

• An imbalance of Yin and Yang

• An excess of Yang leading to a Hot disease

• An excess of Yin leading to a Cold disease

• A deficiency of Yang leading to a Cold disease

• A deficiency of Yin leading to a Hot disease

TCM Diagnosis

An Interior disease is Yin; an Exterior disease is Yang.

Chronic diseases are Yin; acute diseases are Yang.

A Cold natured disease is Yin; a Hot natured disease is Yang.

A deficiency type of disease is Yin; an excess type of disease is Yang.

The underlying causes are Yin; the manifest symptoms are Yang.

TCM Treatment 

A Yang type of disease is given a Yin type of treatment; and a Yin type of disease is given a Yang type of treatment.

A successful clinical outcome is to restore the patient to optimal health, not just to alleviate symptoms The essential features of TCM treatment strategies can be summed up as:

• Increase Yang when there is a deficiency of Yang

• Increase Yin when there is a deficiency of Yin

• Reduce Yang when there is an excess of Yang

• Reduce Yin when there is an excess of Yin

With Yin and Yang as its basis, TCM looks at both the symptoms of a disease as well as its underlying causes. In addition, it is able to go one step further to consider all of these things in the context of the individual’s constitutional strengths and weaknesses as well as the impact of lifestyle and environment on the state of health. A successful clinical outcome is to restore the patient to optimal health, not just to alleviate symptoms, and in doing so to promote a healthy, productive lifestyle and to avoid preventable illness in the future.

As with Yin-Yang, we have a system that begins with simplicity and, being universal in scope, allows for increasing degrees of complexity. Thus, although these concepts may be easily understood, it takes many years of study and experience to be able to apply them successfully in the clinic. Once again, we would like to caution against self-prescribing and recommend that you seek the services of a qualified and registered TCM practitioner for your healthcare needs.