On the Sovereignty over the Diaoyu Islands from the Perspective of Treaties

　　Abstract:Treaties are one of the primary building blocks of international law, and to a great extent, it can be argued that the dispute over sovereignty of the Diaoyu Islands is rooted in the definition and understanding of relevant treaties.In other words, research on the sovereignty of the Diaoyu Islands is inherently related to research on relevant treaties.While no treaty explicitly governs sovereignty over the Diaoyu Islands, analysis of relevant treaties can demonstrate Chinese sovereignty.Both literal and contextual readings of the Treaty of Shimonoseki show that its reference to the concession of “Taiwan and all its subsidiary islands” includes the Diaoyu Islands. It must also not be overlooked that subsequent agreements such as the Cairo Declaration, the Potsdam Declaration and the Sino-Japanese Joint Communique saw Japan return territories taken from China as referenced in the Treaty of Shimonoseki, including the Diaoyu Islands to China.Lastly, neither the San Francisco Peace Treaty, the Treaty of Mutual Cooperation and Security between Japan and the United States, nor the U.S. Japan Okinawa Reversion Agreement specify that the Diaoyu Islands are a possession of Japan.It can be further argued that these later Treaties are rendered invalid as a result of their violation of the principle of Jus Cogens.