Jing is a more elusive type of energy and is not simply produced by the refinement and transformation of chi energy. It is much harder to feel and direct as it is basically what holds you together. More than energy, it is better described as a force. It is the foundation for life, a primordial force that animates life in the first place, the glue that holds your cells together. It regulates growth and form in the same way as DNA but it is not DNA. It is actually the force that holds DNA together; you could call it DNA chi. Jing is found throughout your entire body holding you together, regulating growth and also the flow of chi and production of ching.
You are born with a finite amount of jing which is stored in the kidneys. It is burned up through life itself and as the jing throughout the body is used up you begin to draw on the stores in the kidneys. When these are all gone it will lead to weakness, disease and eventually death. Excesses such as drug use and high stress will deplete the jing faster while inner power martial arts methods combined with tantric sex, or other specific etheric exercises can strengthen it and make it last much longer. By doing such exercises the jing is not only strengthened but the rest of the body becomes strong and healthy so there are less unnecessary loads on the jing.
Jing is used in the production of sperm and eggs but is not simply a part of the sexual energy. It is another level of substance altogether and without it the sperm and eggs would be infertile. Since we only have a finite amount of jing, every time a male ejaculates or a female menstruates some of their jing is lost forever. This is the reason that fertility decreases so dramatically as women age. Also the rate of Down’s Syndrome babies born increases from (1 / 1500 at the age of 25) to (1 / 32 at age 45). The jing is vital for babies as it is this that gives the base of primordial substance for their growth. When a woman has an already-depleted store of jing, less is given to the egg as the woman’s body needs it for her own survival. The same goes for the man accept that each sperm may still have the same amount of jing, but he will produce less of them. Therefore the age of the father is not nearly as important.
When the jing of the two parents combines, it causes an implosion into the lowest material dimensions allowing a massive expansion of the combined jing. Being a primordial substance means that the jing can actually expand enormously by reconnecting with the primordial source from whence it came. At the moment of conception this occurs, therefore expanding the jing given by the parents enormously (only a tiny amount of the mother and father’s jing is given in the sperm and egg so it must expand to give the baby a full store of its own jing). This will never happen again for the given life and this original amount of jing created at conception will last for the whole lifetime. It can then only be strengthened and stored, or expelled and exhausted.
The lower dimensions are the background of all matter in the physical dimensions and hold all things together. It is the ultimate yin energy being totally passive and ready to be formed into anything. It is important to realize that the expansion of jing at conception is an expansion of the combined jing of the sperm and egg. If the jing of either of these is weak or depleted then the expansion will not be as complete and so the life form created will not be as strong and healthy. (Down’s Syndrome is a problem with the DNA and is actually caused by weak jing as this is the force which animates DNA and holds it together).
Jing is extremely precious and should be looked after to the utmost. By strengthening the jing your physical body can become amazingly strong and vitalized. A long and disease-free life can be had with energy to do with as you wish. Your creative powers will not diminish and your brain will stay vigilant to the end. http://www.freepowerkungfu.com gives some important practices for strengthening the jing and also shows how to use the power it can make available. Smashing large river stones with a light slap of the bare hand is just one demonstration of the possible powers of the cultivated jing. In the martial arts chi may be sent into an opponent causing damage to the chi body but to cause internal physical damage or to damage physical objects it is the jing that is used. Jing is the force that can smash material by splitting the actual force that holds that object together. When this is done you do not lose any jing at all. If you were to send chi into an opponent you would lose this chi. When jing is used in the martial arts, your jing simply smashes the jing of the object or opponent.
Another interesting point is that of morning sickness in newly-pregnant women. On a metaphysical level it is caused by the sudden huge expansion of jing in the new life form. As it is inside the mother this force will play havoc with the organs, especially in her sleep when her body is relaxed. Similarly the glowing radiant skin of pregnant women which most people have witnessed is due to the enhanced jing. After giving birth it is not surprising that many mothers suffer from postnatal depression as they suddenly lose the large amount of jing that was in their belly.