‘Realism Diplomacy for a New Era’ in the Kishida Era: Japan’s Security Policy Toward Southeast Asia

‘Realism Diplomacy for a New Era’ (RDNE) is a strategic foreign policy concept proposed by Japanese Prime Minister Fumio Kishida during his administration. Under this framework, Japan has pursued a more proactive and targeted security policy toward Southeast Asia, grounded in a triadic approach encompassing power, interests, and values. Through mechanisms such as asymmetric cooperation, minilateralism, economic security, and value-oriented diplomacy, the Kishida administration adopted a more assertive stance than its predecessors in areas such as multi-bilateral diplomacy, military assistance, and the shaping of an Indo-Pacific regional order. This approach has facilitated Japan’s incremental normalization of its security posture, reinforced alignment with the United States’ containment strategy toward China, and expanded its influence in Southeast Asia. As a result, Japan is poised to enhance its political and military presence in the region. This paper employs the concept of RDNE to analyze the logic underpinning Japan’s evolving security policy in Southeast Asia and assess its future trajectory and regional implications.