This article explores the question of whether Japan is allowed to defend itself under international law and its own constitution. It looks at the history of Japan's Peace Constitution, recent changes to it, the role of the United States in Japan's defense, Japan's Self-Defense Forces (SDF), its military strategy, and international law regarding Japan's right to self-defense. Ultimately, it is concluded that while Article 9 prohibits possession and maintenance of armed forces capable of engaging offensive operations abroad, it does not mean that Japan cannot defend itself against external threats. This can be done through relying on US military support, maintaining its own Self Defense Forces (SDF), using economic, political, diplomatic and technological means for deterrence or taking action within limits set forth by the International Criminal Court (ICC).