This chapter investigates why the Japanese government adopted the Legislation for Peace and Security in 2015, which permitted the limited right to collective self-defence and expanded the latitude of its participation in international peace cooperation activities. The adoption of the Security Legislation appeared to signal Japan’s complete transformation into a ‘normal state’. However, on the one hand, the non-use of force norm constrained the scope of Japan’s military action, resulting in simultaneous institutionalisation of severe conditions regarding the exercise of the right to collective self-defence. On the other hand, the international norm navigated Japan’s security policy, enlarging the scope of Japan’s participation in international peace activities in a way that would not use force.