This paper examines China’s strategic response to the Japan–South Korea entente within the broader context of US-led trilateral security cooperation since the 2010s. Rather than employing conventional wedge strategies such as selective accommodation and coercion, China has pursued a ‘soft wedging’ approach, leveraging rhetoric to subtly reinforce pre-existing divisions without direct intervention. This strategy seeks to discourage South Korea from deepening its alignment with Japan and the United States while minimising the risk of alienating either Japan or South Korea. Drawing on official materials and expert interviews, this study analyses China’s rhetorical tactics in public statements and diplomatic engagements, along with the strategic calculus underpinning its preference for soft wedging. By providing an alternative to more resource-intensive and risk-prone measures, soft wedging broadens the existing theoretical framework of wedge strategies. The empirical analysis further deepens our understanding of multi-target wedging dynamics and China’s strategic objectives in Northeast Asia’s evolving security landscape.