This study compares the China policies of Japan and South Korea under escalating US-China strategic competition and asserts that both states' policy approaches reflect ontological security pursuits. The analysis illustrates how Tokyo and Seoul formulate policies that align with their self-perceived identities within established relational frameworks with the two superpowers to preserve ontological security. The findings reveal that ontological insecurities stemming from abrupt systemic changes or contentious interactions by China drive both states towards strengthened US alignment. Conversely, when ontological insecurities originate from problematic engagements with the US or when there is no insecurity, both states demonstrate an inclination to revitalise economic cooperation with China. The respective patterns of China-engagement strategies and US-aligned balancing against China differ markedly, rooted in distinct identities and interactions among states that generate varying levels of ontological insecurity. By integrating ontological security theory with an empirical analysis of East Asian strategic adaptations to great-power rivalry, the article enhances the theoretical understanding of state behaviour in international relations.
