Jing is the name given to a bodily
energy which differs from the more commonly known
chi energy. While chi is the energy which courses round the
meridians in our bodies and keeps us alive on an immediate basis, jing is more of a long-term concept.
There are two fundamental kinds of jing, these being prenatal jing and postnatal jing. Prenatal jing is the energy formed at conception by the meeting of male and female sexual fluids, and it is the energy which fuels the growth of the foetus in the womb. Postnatal jing is the energy which we take in from the outside world after conception, mostly from ingesting food and drink.
Prenatal jing governs the development of our bodies from conception until adulthood. It is the energy behind all the major bodily changes such as adolescence, and in the long term it determines our general constitution. If we are born with a lot of prenatal jing then our bodily systems will be strong; we will have a good flow of chi and our immune system will be healthy. If, on the other hand, we are born with less jing, then the chances are we will suffer more illness and be more susceptible to allergies, and we will be generally weaker.
However our postnatal jing can, as hinted at above, be strengthened, and this will make up for any loss in prenatal jing, and thus our total jing will be good and we will be healthy. This can be done via regimens such as tai chi or chi kung (qigong), which help to stengthen all the body's vital energies, including our chi and jing, thus promoting a smooth free flow of all bodily energy and keeping everything in working order. Hooray for jing!