Essence

A substance that forms the basis of life and that accounts in particular for reproduction, development, aging, and death. A child is conceived when male and female reproductive essences unite. The combined essence develops, enabling the fetus to form. After birth, the strengthening of the child’s essence causes the body to develop to full maturity. In mid-life, essence starts to weaken and the health and vigor of the body decline.

NB: In a broader sense, essence also means any substance important for life, such as to nutrients in food (essence of grain and water), qì, blood, and fluids.

Essence in Physiology

The importance of essence in the narrow sense has been emphasized since antiquity. The Sù Wèn (Chapter 4) states, Essence is the basis of the body (夫精也, 身之本也 fū jīng yě, shēn zhī běn yě). The Lèi Jīng (类经, The Classified Classic) states, The life [of the individual] receives its life from essence (人生系命于精 rén shēn xì mìng yú), reflecting how health and longevity are related to the strength of essence.

Essence is often referred to as essential qì (精气 jīng qì), the word qì here being used to mean matter in general, rather than the diffuse, active qì that powers the activity of the body. Viewed as a yīn substance, it is also referred to as yīn essence (阴精 yīn jīng).

A broad distinction is made between earlier heaven (congenital) essence and later heaven (acquired) essence.

Earlier Heaven Essence

Earlier heaven is the Chinese way of saying congenital or existing at birth. Earlier heaven essence (先天之精 xiān tiān zhī jīng) is a substance that is inherited by an individual from his or her parents. It is stored in the kidney, and hence it is also called kidney essence (肾精 shèn jīng) or the essential qì in the kidney (肾中精气 shèn zhōng jīng qì). Earlier heaven essence takes the specific form of reproductive essence, which is discussed further ahead.

Earlier heaven essence is the material form with which life begins. The Líng Shū (Chapter 10) states, When human life starts, it first takes the form of essence (人始生, 先成精 rén shǐ shēng, xiān chéng jīng).

Jǐng Yuè Quán Shū (景岳全书, Jǐng-Yuè’s Complete Compendium) states, When [male and female] essences unite, [bodily] form arises. This [bodily] form is essence; essence is [bodily] form (精合而形始成, 此形即精, 精即形也 jīng hé ér xǐng shǐ chéng, cǐ xíng jí jīng, jīng jí xíng yě). The implication of this statement is that essence is a substance that can create an entire living human being, and so the bodily form of a human being essentially is essence.

While essence is the beginning of life, it cannot survive alone. The essence that forms the new embryo is constantly nurtured by the qì and blood of the mother. After birth, earlier heaven essence is partly replenished by later heaven essence.

Later Heaven Essence

Essence generated after birth is called later heaven essence (后天之精 hòu tiān zhī jīng). Because it is extracted from grain and water by the spleen after birth, it is also called essence of grain and water (水谷之精 shuǐ gǔ zhī jīng).

Later heaven essence is transported to the bowels and viscera, to become bowel and visceral essence (脏腑之精 zàng fǔ zhī jīng).

Surplus later heaven essence in the bowels and viscera goes to the kidney to replenish earlier heaven essence. The Sù Wèn (Chapter 1) states, The kidney receives the essence of the five viscera and six bowels and stores it, so when the five viscera are full, they can discharge (肾…受五藏六府之精而藏之, 故五藏盈乃能泻 shèn… shòu wǔ zàng liù fǔ zhī jīng ér cáng zhī, gù wǔ zàng yíng nǎi néng xiè)..

However, earlier heaven essence is not entirely replenishable by later heaven essence and so its eventual exhaustion, which manifests in the waning of vigor in later life, cannot be prevented.

Functions of Essence

Kidney essence is responsible for reproduction and for the development and eventual decline of the human body.

Reproduction: When male and female essential qì unite (男女精气相合 nán nǚ jīng qì xiāng hé), a child is conceived. Hence, kidney essence includes reproductive essence (生殖之精 shēng zhí zhī jīng). During conception, the male reproductive essence combines with the female reproductive essence to form a new fetus.

In the male, reproductive essence takes the form of semen. In fact, in Chinese, jīng 精means both semen and essence. The traditional conception of female essence is not clear. With the influence of modern biomedicine, reproductive essence in the female is now equated with the ovum, but it is important to understand that Chinese physicians never observed ova. It would have been logical for female essence to have been associated with the lubricating fluid secreted during intercourse.

After conception, the combined male and female essence becomes the essential qì of the new individual, which is nurtured by the qì and blood of the mother.

Development of the body: After birth, the kidney essence of the child enables the body to develop. Growth and development reflect a normal healthy strengthening of essence. When the individual reaches his or her prime, the essential qì of the kidney begins a process of weakening that causes the natural decline of vigor and health in advancing age, such as hair loss, loosening of the teeth, and deteriorating hearing and vision.

The following quotation from Sù Wèn (Chapter 1) describes the developmental process. Note that in this text, kidney qì is used in the sense of kidney essence (kidney essential qì).

In females, at the age of seven kidney qì is exuberant, the teeth are replaced, and the hair grows; at the age of two sevens [i.e., at the age of 14] tiān-guǐ (reproductive viability) arrives, the controlling vessel frees, the great thoroughfare vessel is exuberant, the menses come according to their times, and they can bear offspring; at three sevens [i.e., age 21], kidney qì is even, and wisdom teeth grow; at four sevens [i.e., age 28], the sinews and bones are strong, the hair grows to its extreme, and the body is healthy; at five sevens [i.e., age 35] the yáng brightness (yáng míng) vessel is debilitated, the face starts to become haggard, and the hair begins to fall; at six sevens [i.e., age 42] three yáng vessels in the upper body are debilitated, the face is completely haggard, and the hair starts to whiten; at seven sevens [i.e., age 49] the controlling vessels is vacuous, the great thoroughfare vessel is debilitated, and tiān-guǐ is exhausted, the passages of earth are cut, the body deteriorates, and they can no longer bear children.

In males, at the age of eight, kidney qì is replete, the hair grows, and the teeth are replaced; at two eights [i.e., age 16], kidney qì is exuberant, tiān-guǐ arrives, essential qì (semen) flows forth, yīn and yáng are in harmony, and they can beget offspring; at three eights [i.e., age 24] kidney qì is even, the sinews and bones are strong, hence wisdom teeth grow and hair grows to its extreme; at four eights [i.e., age 32], the sinews and bone bulge exuberantly, and the flesh is full and firm; at five eights [i.e., age 40] kidney qì debilitates, the hair falls, the teeth become desiccated; at six eights [i.e., age 48] yáng qì debilitates, the face becomes haggard, the side locks grow white; at seven eights [i.e., age 56], liver qì is debilitated, the sinews cannot move, tiān-guǐ is exhausted, essence diminishes, the kidney viscus grows weak, and the body loses its tone; at eight eights [i.e., age 64], the teeth and hair fall out.

As this passage suggests, the notion of storing essence is reflected in many associations of the kidney. In particular, the growth and decline of the body, reflecting the strengthening and debilitation of essence, find strong expression the development and weakening of bones, hair, and reproductive function throughout the individual’s life.

• In infancy the bones are soft and the teeth (traditionally understood to be the surplus of the bone) are absent, hair is confined to the head and is poorly developed, and the reproductive function is absent.
• When the individual reaches maturity, the bones are strong and not easily broken; the milk teeth have been replaced by permanent teeth; the hair of the head, armpits, and pubes are fully developed; and the reproductive function matures.
• In advancing years, the reproductive function ceases in women and declines in men; the bones become brittle and teeth rot and fall out, the hair of the head thins, grays, and falls out.

When kidney essence is insufficient in infancy, there may be retarded closure of the fontanel gates or other signs of retarded development (slowness to teethe, slowness to walk). When kidney essence is weak in adults, reproductive function is lowered. This manifests in scant semen in men and amenorrhea in women, and in both male and female infertility. When kidney essence weakens prematurely in advancing years, there may be premature signs of old age such as hair loss, deafness, and loss of mental faculties.

Producing qì and blood: Both original qì and blood require kidney essence for their production.

Nourishing: Later heaven essence, which is the essential qì extracted from grain and water by the spleen, is used to nourish the bowels and viscera and the whole body. What is left is stored as a reserve by the kidney. The essential qì in the kidney is constantly drained off to nourish the bowels and viscera.

Resisting disease: Kidney essence is the basis of the health of the whole of the body. Depletion of kidney essence can affect the body’s resistance to disease. The Sù Wèn (Chapter 4) states, When essence is stored, [the individual will] not suffer from warm [disease] in the spring (藏于精者, 春不病温 cáng yú jīng zhě, chūn bù bìng wēn); when essence is not stored in winter, there will be warm [disease] in the spring. (冬不藏精，春必病温 dōng bù cáng jīng, chūn bì bìng wēn) The Jǐn Náng Mì Lù (锦囊秘录 Secret Record of the Brocade Pouch) states, When there is sufficient essence, the hundred diseases will not arise; when there is a lack of essence, the myriad evils swarm (足于精者, 百病不生; 穷于精者, 万邪蜂起 zú yú jīng zhě, bǎi bìng bù shēng; qióng yú jīng zhě, wàn xié fēng qǐ).

Essence as Yīn

Essence is understood to be yīn for the following reasons:

• It is contained in the bowels and viscera and stored in the kidney by the retentive action of qì. Hence it is classed as yīn in relation to qì, which is yáng. Although essence is also called essential qì, the term qì here means matter in general, rather than the diffuse, active qì that power the activity of the body.
• It is described in some texts as specifically being a fluid substance, reflecting the fact that reproductive essence in the male takes the form of semen, while in the female it was traditionally thought to be the fluid secreted during intercourse.
• It is described as having form, since it is the material (yīn qì) from which a fetus develops. It is stored by the kidney, which belongs to the water in the five phases. The water phase represents the phenomenon of storage or hiding in nature (hibernation of animals, reduction of plants to seeds or roots) in the wintertime, the most yīn of all the seasons.

Other Meanings of Essence

The term essence is also used in the literature to mean other things:

Essence, blood, fluids (and qì ): In a loose sense, the term essence refers to blood, fluids (liquid and humor), and according to some sources, qì. Essence, blood, and fluids are sometimes referred to collectively as yīn essence (阴精 yīn jīng). Note that yīn essence may also refer to essential qì.

Essence of grain and water: Remember that the nutrients contained in food are referred to as the essence of grain and water or later-heaven essence.

Right qì: Essence can also refer to right qì, which is an umbrella term for the health-maintaining forces of the body. Sù Wèn (Chapter 28) states, When evil qì is exuberant, there is repletion; when essential qì is despoliated, there is vacuity (邪气盛则实, 精气夺则虚 xié qì shèng zé shí, jīng qì duó zé xū).

Essence in Pathology

Developmental problems such as retarded closure of the fontanels (spaces between the bones of the head) in infants or premature aging are manifestations of insufficiency of kidney essence (肾精不足 shèn jīng bù zú). This is also a factor in male and female infertility. Insufficiency of kidney essence is treated by supplementing kidney essence.

Because semen is a form of essence, the loss of semen in ejaculation, according to traditional understanding, entails a loss of essence. This loss is traditionally perceived to be partially compensated by the essence of the sex partner that is received during intercourse. However, excessive loss over time causes premature decline of the body. Hence, Chinese medicine over the centuries has cautioned against overindulgence in sex, particularly in advancing age. The damaging effects on health of excessive sexual activity are called sexual taxation.

Similarly, childbirth is considered to have a damaging effect on essence in females. However, medical texts from most eras stress the notion that excessive childbirth is damaging to the blood rather than essence. This is related to the notion that the mother’s blood nourishes the fetus during pregnancy and ascends to transform into breast milk after delivery. Moreover, the loss of a large amount of blood during childbirth is obviously taxing to the mother. The importance of blood to women’s health is underscored by the traditional maxim that women have the liver as their earlier heaven. Men’s health, by contrast, was traditionally understood to be more closely related to essence and/or qì.

Essence’s Relationships

Qì and Essence

Essence is understood to be yīn in relation to qì, which is yáng.

Essence transforms into qì: The Lèi Jīng (类经, The Classified Classic) states, Essence transforming into qì means that original qì is formed from essence (精化为气, 谓元气由精而化也 jīng huà wéi qì, wèi yuán qì yóu jīng ér huà yě). For this reason, the health of qì relies on the health of essence. Depletion of essence can cause debilitation of qì.

Qì produces and contains essence: Qì transformation, that is, the transformative action of qì is responsible for the production of essence. The Sù Wèn (Chapter 6) states: Qì turns to essence (气归精 qì guī jīng). When essence abounds, qì is exuberant. Conversely, when essence is depleted, qì becomes weak.

Qì’s containing (retentive) action is responsible for storing essence in the bowels and viscera. When qì gathers, essence abounds; when qì is weak, essence disperses. Essence is stored in the kidney by the retentive power of kidney qì. When kidney qì weakens and its retentive power diminishes, there may be seminal emission, seminal efflux, and clear thin white vaginal discharge.

Furthermore, essence’s control over reproduction, development, and aging is reliant on the action of original qì.

Blood and Essence

The blood also has a close affinity with essence. The essence of grain and water (i.e., later heaven essence) is the source both for producing blood and for replenishing kidney essence. Hence, it is said that blood and essence are of the same source. The term essence-blood (精血 jīng xuè) emphasizes this notion of the shared origin of essence and blood.