In the previous chapters, this book has examined Japan’s nuclear identity, that is, ‘nuclear-bombed state’, ‘nuclear disarmament state’, ‘nuclear-threatened state’, and ‘nuclear umbrella state’ by applying international relations theory (classical liberalism, neoliberalism, classical realism, and neorealism). Each chapter has demonstrated that each nuclear identity has been domestically and internationally constructed and has influenced Japan’s policy toward nuclear non-proliferation and disarmament. Some types of nuclear identity are overlapped and others are incongruous in theory and reality. Are these kinds of Japan’s nuclear identity, however, sustainable or unalterable in the future? Also, can Japan reinforce its own nuclear identity to make a greater contribution to create a world without nuclear weapons? In this concluding chapter, the four types of Japan’s nuclear identity are to be reassessed and policy recommendations for Japanese diplomacy toward the nuclear disarmament and non-proliferation will be taken into consideration.