This article explores the legal reasons why Japan is not allowed to have a military, including its war-renouncing constitution and the Allied occupation of Japan following World War II. It also looks at the current status of the Japanese Self-Defense Forces (JSDF), international criticism of them, Japan's military spending and defense capabilities, and its role in regional security and cooperation. Despite being legally prohibited from having a traditional military force, Japan still has limited defensive capabilities through its Self-Defense Forces, as well as playing an important role in regional security through diplomatic means.