Seong-Hyon Lee argues that the trilateral relationship between South Korea, Japan, and China is currently at a critical juncture as historical legacies, territorial disputes, and the evolving geopolitical landscape pose significant challenges to meaningful cooperation and undermine future collaborative efforts among the three countries. Lingering animosity resulting from historical memory and conflicting territorial claims can be easily provoked and challenge efforts by the three countries to form any kind of common trilateral unity. Such obstacles are further complicated by the impact of the US-China rivalry on the geopolitical landscape in East Asia. Despite growing ties between the United States, South Korea, and Japan to counterbalance China’s assertive regional policies, Lee highlights various motivations that both South Korea and Japan have for enhancing cooperation with China. South Korea and Japan desire a relationship of mutual benefits and reciprocity with China, and China serves as the largest trading partner for both countries. While economic interdependence and a balanced division of labor within the regional supply chain had previously facilitated trilateral cooperation, South Korea’s economic vulnerability to Chinese retaliation and growing industrial competition among the three countries have eroded a major impetus to cooperate and reduce tensions. Lee recommends that the three countries engage in proactive efforts to foster mutual trust and understanding, noting that the future of the trilateral relationship will depend on the strategic choices made by the leaders of South Korea, Japan, and China.