Jing (Chinese: 精; pinyin: jīng; Wade–Giles: ching1) is the Chinese word for "essence", specifically Kidney essence. Along with qi and shen, it is considered one of the Three Treasures of traditional Chinese medicine.
According to Traditional Chinese Medical theory, jing or essence can be summarised in two parts: the Yin, being congenital or prenatal, and the Yang, being postnatal or acquired. Prenatal jing is acquired at birth from the parents: the father's sperm and the mother's ovum. This is a similar concept to DNA. Postnatal jing is acquired after birth through food, water, oxygen, as well as environmental and social conditions—very much like the concept of epigenetics. The concept is expounded in the Chinese theoretical cosmological treatise called the Bagua and within the I Ching.
The Yin and Yang jing transform to create and replenish each other. The Yang jing circulates through the eight extraordinary vessels and transforms to become and replenish yin; in turn the marrow becomes blood, body fluid and semen.
Jing should not be confused with the related concept of Neijing (勁; "power"), nor with jīng (經; "classic"), which appears in many early Chinese book titles, such as the Huangdi Neijing, Yijing, and Chajing.
The characteristics which constitute signs of good jing (e.g. facial structure, teeth, hair, strength of adrenals or Kidneys) share the embryological origin of neural crest cells. These cells undergo immense and challenging cellular migrations requiring great organisation. As such, jing may simply represent the strength of embryological self-organisation in the organism. This will be manifested most strongly in those cells which require most organisation; that is, the neural crest cells.
One is said to be born with a fixed amount of jing (prenatal jing is sometimes called yuanqi) and also can acquire jing from food and various forms of stimulation (exercise, study, meditation.)
Theoretically, jing is consumed continuously in life; by everyday stress, illness, substance abuse, sexual intemperance, etc.
Prenatal jing is very difficult to be renewed, and it is said it is completely consumed upon dying.
Jing is therefore considered quite important for longevity in traditional Chinese medicine (TCM); many disciplines related to qigong are devoted to the replenishment of "lost" jing by restoration of the post-natal jing and transformation of shen. In particular, the internal martial arts tai chi, the Circle Walking of Baguazhang and the middle path of Wuxingheqidao may be used to preserve pre-natal jing and build post-natal jing, if performed correctly. In Traditional Chinese herbal medicine Ginseng is widely used to bolster and support the jing or Essence.
An early mention of the term in this sense is in a 4th-century BCE chapter called Neiye "Inner Training" of a larger text compiled during the Han dynasty, the Guanzi.