The Ministry of Defense of Japan claimed sovereignty over Dokdo (Dokto, Japanese name: Takeshima) in the “Defense of Japan”. This is the 17th time that Japan’s Defense of Japan has claimed Dokdo sovereignty. Defense Minister Nobuo Kishi reported the 2021 Defense White Paper (“Defense of Japan”) at a cabinet meeting on the 13th. The white paper clearly states that “the territorial issues of the Northern Territories and Takeshima, which are territories peculiar to Japan, still remain unsolved.” Japan first published the Defense of Japan in 1970. Published annually since 1976, Dokdo’s claim of sovereignty was first described in 2005. Especially this year, the Tokyo Organizing Committee for the Olympic and Paralympic Games displayed Dokdo on a map depicting the torch relay course with fine dots like Japanese territory, which was controversial. Under these circumstances, the Japanese government issued a Defense of Japan claiming Dokdo sovereignty 10 days before the opening ceremony of the Olympics. In this year’s Defense White Paper, “Negative response by the Korean defense authorities” while maintaining the description of last year that “the issues between the Japanese and Korean defense authorities are affecting the defense cooperation and exchanges between Japan and South Korea” The claim that “is continuing” was additionally stated. In addition, this year’s Defense of Japan, as it was last year, contained the content that the Japanese side is requesting the South Korean side to take appropriate measures to resolve the concerns. The expression “Do not impair cooperation” was added. It is analyzed that this is a “negative response by the South Korean side” and claimed that there could be a problem in defense cooperation between the three countries of Korea, Japan and the United States.