As the United States and South Korea expressed solidarity in blaming North Korea for its attack on the South Korean warship Cheonan, followed by North Korea’s artillery attack on Yeonpyeong Island, and in imposing further sanctions on North Korea, global attention is now focused on China with regard to whether it will cooperate in imposing punitive measures on its ally. Despite the worsening cleavages between China and North Korea since October 2006 when the latter tested its nuclear weapons, this study shows that their relations have remained robust in the economic context although they are experiencing a political transition. This paper begins with Sino-DPRK relations by exploring the status of the alliance in transition in the political and military context. Further, it considers the economic context between the two nations by reviewing Chinese aid to North Korea and North Korea’s trade data, using the “flow of goods” as a proxy for “flow of money.” Then, this paper applies North Korea’s strategic interaction with the United States in the game-theoretic methods in order to illustrate the Chinese impact on the effectiveness of economic sanctions on North Korea. The study found that China’s role remains consequential, as the strategies of North Korea and the United States depend on China’s position.