This chapter is concerned with alternative competition and concurrence between the United States and China in the context of East Asia, particularly the strategic significance of the rivalry between the two countries in the mechanism for establishing a global international order. The hegemonic influence is deteriorating further in the wake of the 2008 financial crisis and is thus even more challenged by the United States’ dominant position in the global arena. In the meantime, as a state with rapid economic growth and political aspirations, China has become one of the serious rivals to American hegemony and, more specifically, after its successful recovery from the 2008 crisis and the restoration of its status as the second-largest economy in the world. The chapter examines the character of U.S.-China relations, with special focus on the economic, political, and military dimensions of their rivalry in East Asia. Another problem under examination is China’s endeavors, including the Belt and Road Initiative (BRI), and its political game in the area’s security process. The chapter ultimately concludes that, despite increasing competition, there is still cooperation in certain world-related matters with tremendous implications for the stability of East Asia and world peace.