Northeast Asia served as the focal point of China’s Asia policy; but Southeast Asia came a close second. Of the two subregions, mainland Southeast Asia occupies the most prominent position in China’s regional policy both because it lies on its southern periphery and because of Beijing’s ambitions to integrate the economies of its southwest provinces with those of Thailand, Myanmar, Vietnam, Cambodia and Laos. In terms of culture, religion and political systems, China was also more attuned to the countries of mainland Southeast Asia than those further south. Yet China’s largest regional trade partners were located in maritime Southeast Asia. Moreover, as the PRC increasingly looked to the oceans to help fulfill its developmental goals and Great Power aspirations, Southeast Asia’s vital sea lanes assumed much greater importance. Taken as a whole, Southeast Asia not only offered China attractive economic opportunities, but the absence of a dominant actor, either indigenous or external, provided it with greater latitude to expand its political influence than in other parts of the Asia-Pacific. A cordial relationship with ASEAN offered China the chance to play a leading role in shaping the development of regional architecture and, in the process, further its influence.