The major source of CHI comes from the various forms of liquids and hormones produced in our body. This includes blood, the hormones secreted by glands in our body and the sexual fluids. Together, they form the CHING or JING! Thus, JING is the essence of our life!
Jing also refers to the essential nature of all things. Everything in the universe has Jing, living or dead! Food and breath are the main sources of Jing outside our body! As we age, the primary source of Jing in our bodies come from our sexual organs. In men it is found in the Semen and in women in the Ova. As we reach adulthood, the sexual Jing converted into Chi becomes the body's primary driving force!
The Taoists realised that loss of semen resulted in loss of Jing in men and the same happened with women during menstruation. The Taoists came up with various ways to preserve this almighty JING!