This chapter applies the analytical framework discussed in Chapter 1 to Japan’s case and defines key concepts, including Japan’s domestic norm, the various interpretations of the norm among political parties, and the international norm. It argues that Japan’s national norm is the non-use of force, which is symbolised by Article 9 of the Constitution. However, during the Cold War, there were roughly two interpretations of the non-use of force norm: one was an anti-militarist perspective that denied anything military. This view was supported by the left, including the Japan Socialist Party and the Japanese Communist Party. The other was the ‘normal state’ view, which supported Japan’s contribution to global peace within the limits imposed by the Constitution. This perspective was supported mainly by the Liberal Democratic Party. Although both groups shared the same norm of the non-use of force, their interpretations of when and to what degree force could be used varied. The chapter then defines the meaning of the international norm discussed in this book. The international norm, which consists of making troop contributions to global peace, suddenly gained political visibility in the post-Cold War era. This norm, the book argues, influenced the direction of Japan’s security policy.