It cannot but be noted that the Japanese Territorial Sovereignty Exhibition Hall, which reopened in 2020, has emphasized Japan's legal control over Dokdo and Kore a's illegal occupation since 1905. This is because not only is the history of Japan's continued invasion of Dokdo's sovereignty based on Japanese colonialism, which is the basis of the Japanese imperial ist invasion route, still ongoing, but also disproves that Japan's attempt to invade Dokdo Island is resuming in 1905. In the process of tracing and examining legal problems of the genealogy the researc h on the legal principle of titles of Japanese Society of international law, which is establishing the policy basis for Japan's claim to Dokdo based on Japanese colonialis m, the genealogy of Japan's claim to Dokdo is the 'theory of historical title' by Takeshi Minagawa,'the theory of original title' by Toshio Ueda, 'the theory of subsitutional title' by Kanae Daijudo, and 'the theory of common occupancy' by Gentaro Cerita. After the ‘the theory of effective territorial title’ based on 'the view of history on international law by Yoshio Hirose, which is the peak of the genealogy of the title of Dokdo sovereignty, international legal scholar such as Takashi Tsukamoto and Tetsuya Nakano, who appear as mainstream researchers, are cannot but be notedthat all classified as genealogy of 'the theory of original title on terra nullis' and are in line with the claims of the Territorial Sovereignty Exhibition Hall. In particular, Tsukamoto argues that it is necessary for Japan to reinforce uncertai n primitive title under modern international law through an territorial acquisition process based on effective possession such as occupation of territory with historical title in the 17th century. On that premise, it is analyzed that the issue of Korea's Dokdo name is used as the basis for terra nullis theory when examining Tsukamoto's historical perception related to the Dajokan Directive of State in 1877, Korean Empire Edict No. 41 in 1900, and Dokdo incorporation in 1905. However, Japan is also facing limitation s, such as diluting the problem of calling Ulleungdo Island to Takeshima in the the Dajokan Directive of State into confusion caused by the influx of Western maps due to its opening. On the other hand, unlike Takashi Tsukamoto, Tetsuya Nakano raises the preem ption theory based on the international law relationship after the Treaty of Ganghwa Island in 1876, on the premise of some insulation from the historical title, but since the 1904 Korea-Japan Protocol, it ignores the illegal problems of Japan's claim to Dokdo as a separate concept. His claim is clearly expressed in the issue of notification as a preemption requireme nt, and it is interpreted that there is no international law principle that it is an absolute requirement for the acquisition of a territorial power, while acknowledging the gener al protocol of the Berlin Conference in 1885 and the obligation of the International Law Society in 1888. In other words, Nakano criticized that there is no international case of reaffirming its own territory in order to confirm its territory in the modern international legalsystem based on the principle of sovereignty equality, but it is noteworthy that it violates the principle of sovereignty equality since the 1904 Protocol and claims that Japan's invasion of Dokdo and other invasions are based on legal rights under international law. To sum up, Takashi Tsukamoto has limitations in that it follows the legal problem s inherent in 'the theory of subsitutional title' by Kanae Daijudo and distorts Japan's confusion with the name of Dokdo. While Tetsuya Nakano insisting on the modern international legal system based on the principle of equality of sovereignty, it exposes the limitations of legalizing Japanese colonialism in issues such as the invasion of Dokdo sovereignty and notification issues. In addition, the same terra nullis insisters as Hirose Yoshio, should not be arbitraril y interpreted and used the Clipperton case, the Eastern Greenland case and the Mang kie Ecreo case, as cases which related to uninhabited islands, isolated locations and effective control. Therfore, it should be noted that the genealogy of the study related to the title of the Japanese Society of International Law, which has established the policy basis of Japan's claim over Dokdo, is consistent with Japanese colonialism as the essence of violence and greed proclaimed in the Cairo Declaration. Moreover, Japan's claim to Dokdo, which attempted to separate it on the premise of “legitimate theory of colonial rule” which raised by terra nullis insisters after ‘view of history on international law' by Hirose Yoshio, which is the epitome of the genealo gy of the title related to Dokdo sovereignty, is a legal distortion of international legal title and a serious legal infringement of Korea's Dokdo sovereignty. I would like to urge Japan's international legal responsibility for the 21st century peace community.