Nuclear strategy of the US-Japan Alliance is facing the most dynamic change of strategic milieu since the end of the Cold War. North Korea conducted two nuclear tests. China’s military build-up is expanding rapidly, particularly in its nuclear capability and maritime forces, to start challenging the US dominance in contesting areas such as the South/East China Sea. In spite of political relaxation over the Taiwan Strait, China continues deploying over 1300 nuclear-capable ballistic missiles targeting Taiwan and US forces in Japan. On the other hand, President Obama’s government has shifted its nuclear policy to nuclear disarmament, eventually toward “a world without nuclear weapons”. Nuclear Posture Review Report (April 2010) details concrete action plans toward global nuclear disarmament while maintaining nuclear deterrence with lower level of strategic stability vis-à-vis Russia and China. The US and Russia agreed in April 2010 to reduce the number of strategic weapons. The report also suggests “expand consultation with allies and partners to address how to ensure the credibility and effectiveness of the US extended deterrent”. Japan, hosting the largest US overseas forces while facing increasing nuclear threat in the region, is in a critical moment to re-examine its defence policy in general, and the US extended nuclear deterrence (“nuclear umbrella”) in particular. Apart from President Obama’s initiative for nuclear disarmament, the current Japanese liberal government takes rather radical stance to re-course nuclear strategy of the US-Japan alliance. Foreign Minister Okada took the liberty of proposing ‘negative security assurance’ or ‘no-first use policy’ that would, if taken seriously by the US, induce fundamental shift of the US nuclear strategy. The security and strategic situation in the Asia Pacific is dramatically changing, which would certainly affect the effectiveness of the US extended nuclear deterrence. Despite that, there is no deep and detailed discussions or mutual consultation on this vital issue between Japan and the US. This is partly because of Japanese traditional hesitance to discuss on nuclear strategy (‘nuclear taboo’), and lack of communication between the two governments amid prolonged Futenma controversy. In Japan, the nuclear strategy debate has been constrained to professionals and officials, with negligible scrutiny from the academia. The project will bridge those professionals, officials and academics in Japan and the US to enhance realistic and pragmatic debate on this important issue. The project will address the following questions: • How does the US nuclear strategy toward East Asia change by the latest US-Russia agreement for reduction of strategic nuclear weapons, which will place China within the reach of new strategic parity vis-à-vis the US and Russia? • How does the US extended nuclear deterrence work vis-à-vis tactical nuclear missile threat from North Korea and China? • What is the impact of missile defence on nuclear deterrence? • Will the US-Japanese missile defence provide positive effects on the Asia-Pacific in terms of security, arms race, and nuclear proliferation issue? • How does missile defence interact with global efforts toward nuclear disarmament? • An alternative option of nuclear strategy for the US-Japan alliance