What is the impact of the U.S. return to Asia on Sino-Japanese strategic competition? This paper argues that as Washington pivots to the Asia-Pacific, situation of their competition deteriorates quickly. Previously, the U.S.-Japan alliance, as described in Thomas Christensen’s theory in 1999, possessed dual deterrence and was able to preserve peace and stability in East Asia-deterring military threats from China and North Korea, andpreventing the remilitarialization of Japan. Currently, however, these functions have been disrupted by China’s military modernization and challenged by Japan’s security transformation. The key to this situation is Beijing’s rise, economically and militarily, in recent years. This development is subtly undermining Christensen’s 1999 argument that the U.S.-Japan alliance could resolve problems associated with the China-Japan security dilemma and lower the likelihood of arms races, military confrontations, and war between these two nations.