The aim of this study is to provide the reader with a better understanding of the evolution of Japan's cybersecurity and defense policy since the year 2000. In addition to the policy areas in which the Japanese government is active in protecting cyberspace, the report explains the security-​related events that have triggered the need for government involvement. In addition, the report analyzes the key strategic documents that are still shaping Japanese government behavior and thinking on cybersecurity, and examines how cyber security is organized in Japan (ministries, agencies, councils and more). It should be noted that this study only deals with organizations and instruments in which the Japanese government itself is involved. Therefore, it does not fully describe the developments and dynamics of the private sector in Japan.