This is part of a series of lectures on Qin Bowei's 56 methods. This lecture will focus on Qi and Qi related disorders. We discuss the source, causes, mechanism, locations, disease manifestations, and presenting symptoms leading to a broad picture understanding of Qi. The associated treatment principles of Qi will also be covered along with key diagnostic criteria for each principle, the associated flagship formula for each, how to modify it, and how it relates to classical Chinese medicine. Finally, we will go over numerous case studies to demonstrate how this system is used effectively in clinic.