This Chapter is a dialogue from the Yellow Emperor's Classic of Internal Medicine, exploring the principles of acupuncture's Nine Needles. Qi Bo, explaining to the Yellow Emperor, details how these needles treat imbalances of yin and yang by addressing fullness and deficiency in the body. The techniques described involve precise needle insertion and manipulation, timed to align with the body's energy flow. Specific acupuncture points are identified, and the broader philosophical context links the practice to the cosmos, emphasizing the interconnectedness between human physiology and the natural world. Ultimately, the text aims to codify acupuncture techniques for future practitioners.