Qi concept in TCM is basically the vital force of life that flows in the body and throughout the body in order to exchange carbon dioxide with the atmospheric oxygen in order to be alive. Therefore, this Qi is called Qing Qi 清气 or the Qi of Heaven & Earth since all lives are dependent on this Qing Qi / the atmospheric oxygen.

Once the Qing Qi 清气 is breathing into our body, it sustains every single molecule, cell, tissue, organ and organ system in the body.

However, once the Qing Qi is flowing into each organ systems, it becomes different name of Qi in relation to a particular organ system. For instance, the Qi circulates the lungs, will be called Wei Qi 卫气 which defends the body from external invasions such as any airborne infection etc.

Once the Qing Qi goes through the whole body and it anchors with the inherited original Qi from birth or Yuan Qi 原气, it becomes genuine Qi 真气. It is this Genuine Qi which is the most important Qi that moves and transforms all the living molecules, cells, tissues, organs and organ systems in our body for maintaining, surviving and keeping the body in the relatively healthy state.