Territorial sovereignty of Korea over Dokdo is out of doubt from the historical and international law perspective. The Korean title to the small islet could be under international law supported or proved by original title, acquisition by conquest, historical consolidation, effective control and the supremacy in relative title. Nevertheless, Japan has incessantly contested the Korean sovereignty over Dokdo and made every possible effort to submit the territorial dispute to the International Court of Justice. So we should prepare for pertinent responses in advance to cope with the situation where the Dokdo issue is referred to the international court. Considering all the possible "critical dates" to be adopted by an international tribunal, the Korean government must collect evidences on the display of the Korean sovereignty over Dokdo, including enactments, administrative measures, documentary evidences etc. and systematically arrange them to present before the international court in each case.