There is nothing more fundamental to Asian bodywork than understanding the concept of Qi (pronounced "chee" also written as Chi).
Qi has been translated as "vital energy" or "life force"; but, it is impossible to capture the concept fully in one English word or phrase. Everything is composed of Qi even though it is not seen as some fundamental particle, substance, or energy.
The Chinese say,"When Qi gathers, the physical body is formed; when it scatters the body dies."
What are the Channels?
It is tempting to think of the channels in the same way as we think of the system of blood vessels - arteries, veins, and capillaries - that carry blood around the body. This is both a useful and a misleading analogy. It is useful in that the channel system is responsible for transporting Qi through the body, but it can be misleading because Western anatomy and physiology wouldn’t be able to identify these pathways in a physical sense the way the that blood vessels can be.
A useful analogy, to describe Qi flow, is a river. A river has a source and it follows it’s course toward the ocean. As it flows it will vary from shallow to deep, rapid to slow, while always following the most natural path.
Now we have the picture of the body being permeated by an energy system concentrated around areas of high-density energy, called channels. This energy moves in specific ways, driving the processes that makeup the body. If anything happens to weaken or block this flow of energy, there can be an energetic imbalance that will manifest itself as pain or illness.