This article explores the history and importance of Japan's alliances, with a particular focus on the United States which is currently its most important ally. It looks at the benefits of this alliance for both countries, including increased security, trade opportunities and investment opportunities. It also looks at other key allies for Japan such as South Korea, Australia, India and Russia among others. Finally, it looks at how these alliances may develop in the future and how they will remain crucial partners for Japanese security interests.