This paper examines the arguments and facts regarding the Japanese National Assembly's claim to Dokdo sovereignty. The Japanese National Assembly's claim to Dokdo sovereignty is that ‘Japan recognized Dokdo before Korea.’ After the Pacific War ended and the post –war Japanese National Assembly was officially opened, the National Assembly continued to assert Japan's inherent territory over the Northern Territory (Kuril Islands). In other words, Japan at the time created the logic of its own territory in order to regain the northern territory that had been occupied by the Soviet Union, and the northern territory was Japan's inherent territory. So, from this time, Japan defines its inherent territory as, firstly, the territory acquired by Japan through treaties, and secondly, the places where Japanese people have lived in the past as Japan's inherent territory. However, around the time of the signing of the San Francisco Peace Treaty, the concept of indigenous territory in the Japanese National Assembly diverged from the existing logic. The existing logic of indigenous territory changed from the concept of indigenous territory as ‘territory acquired by Japan through treaties' and ‘places where Japanese people have lived since the past’, and when the San Francisco Peace Treaty was concluded, the concept of Japan's indigenous territory changed. The changed content claims that ‘places that are not recorded as territories excluding from Japan under the San Francisco Peace Treaty or that can become Japanese territory based on geography or international law’ are claimed as Japan's inherent territories. In the process, Dokdo was mentioned as Japan's inherent territory, a logic based on Shimane Prefecture's Notice No. 40 of 1905 for ‘occupation of terra nullius territory.’ Therefore, this paper reveals the limitations of Japan's claim to Dokdo as its inherent territory through an analysis of the minutes of the Japanese National Assembly.