This Chapter is a dialogue from the Yellow Emperor's Classic of Internal Medicine, exploring different patient responses to acupuncture. Qi Bo, a master, explains that varied reactions—such as immediate qi flow, delayed response, or reverse qi flow—stem from imbalances of yin and yang in the patient's constitution. He attributes successful needling to a balanced state, while adverse reactions result from the practitioner's technique, not inherent patient imbalances. The discussion focuses on how a practitioner can diagnose and treat patients based on their unique energetic constitutions. The text provides a framework for understanding the principles behind acupuncture treatment and the importance of practitioner skill.