Guiguzi, also known as the “Sage of Ghost Valley,” is a semi-legendary figure in ancient Chinese philosophy, often associated with the origins of the School of Diplomacy (Zonghengjia) and known for his teachings on strategy, persuasion, and diplomatic tactics. While the exact details of his life are unclear, he is reputed to have lived during the Warring States period. The text attributed to him, “Guiguzi,” is considered a foundational work on the art of persuasion and diplomacy, exploring techniques for influencing and negotiating with others.