Remember that whole TPP thing? Cancelling that must have made China very happy.

«the widely reported campaign against South Korean economic interests following Seoul’s decision to participate in the United States-led Terminal High Altitude Area Defense (THAAD) missile defense program, announced in July 2016, offers a valuable case study. The THAAD dispute represents a broad-based coercive episode directed at an ostensibly vulnerable target: China is South Korea’s largest trading partner—the destination of approximately one quarter of its total merchandise and service exports at the time of the dispute—and therefore essential to national GDP, 40 percent of which comes from exports. By contrast, South Korea was the source of just 10 percent of Chinese merchandise imports and did not feature among the mainland’s top service suppliers.»

https://theasanforum.org/chinese-economic-coercion-during-the-thaad-dispute/