The basic notion of Qi.
Universal Cosmic Energy that bathes us is called the Qi.
There is good Qi (Sheng Qi) and bad Qi (Sha Qi).
It is this same energy that yogis call prana, that ancient alchemists tried to capture, that Acupuncture regulates and that Eastern gymnastic or martial arts (Karate, Tai-Chi-Chuan, Qi-Gong) use.
It's also the same cosmic energy that is used in Holistic Medicines (Reiki . . . ) and it probably can be compared to the Holy-Spirit that falls in tongues of flame during the Pentecost.
It flows inside the human body, along the acupuncture meridians, until death.
You can try our software Chronos which shows how the energy circulates and which computes the Acu-Points opened at a given time (Chono-Acupuncture, Zi Wu Liu Zhu and Ling Gui Ba Fa techniques): download and try at http://www.delemme.com/ftelchronos.htm
The art of tracking the Qi is called Li Qi or Li Fa.