This Chapter from The Yellow Emperor’s Classic of Internal Medicine details the principles of Qi (vital energy) in Traditional Chinese Medicine. It distinguishes between Wei Qi (defensive Qi) and Ying Qi (nutritive Qi), explaining their flow through meridians. The text further describes the locations and connections of the twelve primary meridians, diagnosing imbalances (deficiency and excess) based on their symptoms, and recommending treatment methods focusing on Qi intersections to alleviate various ailments. Finally, it addresses diagnosing the location and type of Qi imbalance to determine appropriate treatment.