Japan's decision since 1999 to conduct joint research with the US into the development of an anti-ballistic missile, TMD system has major implications for its security policy and international relations in East Asia. TMD is likely to enhance Japan's bilateral security cooperation with the US and South Korea, but also to generate new security tensions amongst Japan, North Korea, Taiwan, and especially China. This research project is the first to investigate the policy-making process behind Japan's decision to participate in TMD and the specific consequences for its relations with the US and the stability of the East Asia region. The project will enhance theoretical and empirical knowledge of Japan's security and diplomatic policy in the fields of Japanese Studies, and International Relations. The research will be carried out by fieldwork at the University of Tokyo designed to gather Japanese language documentary evidence and conduct interviews with policy-makers.