Ch'i which translates as breath or energy is an invisible force which flows around us and within our body. The actual form of this energy is difficult to express and has been thought of as an electro-magnetic force, or as airbourne particules known as 'ling'. At its most basic level Chi energy is composed of the opposition between Yin and Yang, which can then be refined into the Five Elements of Ch'i, the Nine Ki, and further still.
The Ch'i flows around us in a similar manner to wind or water (hence the term Feng Shui), displaying the same ebbs and currents and it is this that Feng Shui tries to affect. By using the techniques laid out in Feng Shui teachings, the goal is to create a harmonious flow of Chi energy through moderation and enhancement.