Russia's relationship with China is complex and contradictory. Bilateral ties are more substantive and multifaceted than ever before, the two countries agree on most regional and international questions, and China is a major customer of Russian arms and energy. However, Moscow is increasingly uneasy about China's transformation as the next global power and the implications of this for Russia's security and place in the world. Balancing delicately between strategic convergence and suspicion, Sino-Russian partnership faces an uncertain future.