|This article is part of the philosophy of CAM and series of articles.|
Jīng is the Chinese word for "essence", specifically kidney essence. Along with and , it is considered one of the ''Sanbao'' 三寶 of Traditional Chinese Medicine or TCM. Jīng is stored in the kidneys and is the most dense physical matter within the body . It is said to be the material basis for the physical body and is '''' in nature, which means it nourishes, fuels, and cools the body. As such it is an important concept in the internal martial arts. Jīng is also believed by some to be the carrier of our heritage . Production of semen, in the man, and menstrual blood , in the woman, are believed to place the biggest strains on jīng. Because of this, some even equate jīng with semen, but this is inaccurate; the jīng circulates through the 8 extraordinary vessels and creates marrow and semen, among other functions.
One is said to be born with a set amount of jīng and also can acquire jīng from food and various forms of stimulation Theoretically, jīng is consumed continuously in life; by everyday stress, illness, substance abuse, sexual intemperance, etc. Pre-natal jīng by definition cannot be renewed, and it is said it is completely consumed upon dying.
So, this jīng is considered quite important for longevity in TCM. Many disciplines related to are devoted to the replenishment of "lost" jīng by restoration of the post-natal jīng. In particular, the internal martial arts and the Circle Walking of Baguazhang may be used to preserve pre-natal jīng and build post-natal jīng - if performed correctly. Commonplace in China is the sight of on sale in herb shops, at a wide range of prices - Kung Fu classics fans may remember it used as a plot element at the start of Drunken Master 2. Rénshēn, particularly Korean and Chinese, is said to bolster the jīng and a common medicinal recipe is to add to porridge along with cinnamon, goji berries and ginger for a sweet, warming breakfast when the weather starts to turn cold in Autumn.
An early mention of the term in this sense is in a 4th century BCE chapter called "Inner Training" of a larger text compiled during the Han dynasty, the .
Jīng should not be confused with the related concept of , nor with jīng , which appears in many early Chinese book titles, such as the , and , the fundamental text on all the knowledge associated with tea.