Since being applied to U.S.-Soviet-China trilateral relations after the Sino-American rapprochement in the early 1970s, the notion/theory of “strategic triangles” has been widely used to examine many trilateral relations. The model of “U.S.-China plus one” is popular among students of U.S.-China relations and, consequently, the policy community has witnessed an increasing amount of scholarship on triangles among U.S.-China-India, U.S.-China-Japan, U.S.-China-Russia, and even U.S.-China-Taiwan. Unsurprisingly, this begs the question whether a strategic triangle could be construed and constructed among the United States, China, and South Korea. Generally speaking, despite the trilateral nature of U.S.-China-ROK relations, the Chinese policy community rarely subscribes to the existence of a strategic triangle among the U.S., China, and South Korea. This is not necessarily because South Korea does not carry the same strategic weight as the two great powers, but more importantly is because China does not see South Korea as possessing the strategic autonomy to act as an independent player in the trilateral relations. Although arguably such autonomy might exist in economic and trade relations, on key political and security issues, the Chinese see South Korea as invariably constrained by the U.S.-ROK military alliance and unable to form its own independent national security policy.

In writing about the post-Cold War period with an emphasis on geopolitics, Chinese authors do not often treat South Korean policy or Sino-ROK relations as autonomous. Given the great weight given to the U.S. role, it is important, therefore, to take a triangular approach in assessing these writings centered on South Korea. I do so first explaining in more detail why the “strategic triangle” framework does not apply, then examining views on how this triangle has evolved in a period of rising Chinese power relative to U.S. power and fluctuating U.S.-ROK relations as the leadership in Seoul changed hands, and finally returning to the triangular theme to grasp how this shapes China’s understanding of Seoul’s policies with emphasis on the ongoing Moon Jae-in era.