This chapter explores the intricate relationship between geography and military strategy in ancient China, focusing on the strategic importance of the Guanzhong regionGuanzhong/Guanzhong plain/Guanzhong region. It highlights that China’s core leadership expanded its strategic space through the interaction of grand strategy and geography. The west-to-east expansion often saw western powers triumph over eastern ones, emphasizing Guanzhong’sGuanzhong/Guanzhong plain/Guanzhong region geographical advantages. Concepts like the “fundamental base” and “regions of strategically advantageous terrain, naturally fortified on all sides” underscore Guanzhong’sGuanzhong/Guanzhong plain/Guanzhong region significance as a natural fortress and agricultural base. Two major strategic processes were the development of political space from west to east and the flow of population from north to south, influenced by geography, politics, and the economic foundations of the Yellow and Yangtze River basins. The Huai River basin’sHuai River basin strategic position and the Great WallThe Great Wall’s geographical significance as an agricultural-pastoral transitional zone further demonstrate geography’s decisive role in military and political affairs. Through historical case studies, such as King Wu of Zhou’s campaign against King Zhou of Shang, the Qin’s unification of the six states, and the Chu-Han Contention, the lecture showcases geography’s crucial role in political transitions.