There is a longstanding sovereignty dispute concerning the Diaoyu/Senkaku Islands between China and Japan. An “international dispute” is a matter for objective determination: one exists if “there is a disagreement over of point of law or fact, a conflict of legal views of interest” between two parties, as it was stated by the Permanent Court of International Justice in the Mavrommatis Palestine Concessions (Jurisdiction) case (1924). Therefore, a mere denial from the Japanese government that the dispute exists does not prove the nonexistence of the dispute.
China and Japan obviously have contradicting legal positions on the Diaoyu/Senkaku Islands. Previous Chinese literature invokes historical evidence dating to before the Sino-Japanese war to prove China’s sovereignty over the islands. For China, the “fact” that the islands were uninhabited does not mean that Diaoyu Islands were “terra nullius” under international law. Besides the fact that China had already discovered and named the Diaoyu Islands by the 14th-15th century, it is general knowledge that the maritime boundary line between China and the Kingdom of Ryukyu (invaded and then renamed as “Okinawa prefecture” in 1879 by Meiji government of Japan) was in Hei Shui Gou (today’s Okinawa Trough) between Chiwei Yu and Kume Island. The Diaoyu Islands, lying to the west of Hei Shui Gou, were China’s territory, not islands appertaining or belonging to the territory of the Ryukyu Kingdom.
Prior to the 1895 Japanese Cabinet decision that “incorporated” the Diaoyu Islands into Okinawa prefecture, the Diaoyu Islands had long been under the Chinese coastal defense of the Ming (1368-1644) and Qing (1644-1912) dynasties. The Qing court further placed the islands under the jurisdiction of the local government of Taiwan. This can be proved by numerous official documents or maps originating from China, Japan, and the Kingdom of Ryukyu.
Japan, on the other hand, relies on the theory of territorial acquisition under modern international law to defend its claim. For example, a recent article by Jun Tsuruta in The Diplomat referred to the rule of “effective control” in international law, especially “terra nullius” and “acquiescence,” and concluded that “China’s long postwar silence undermines its claim to sovereignty.” However, according to the Tripartite Hierarchy Rule for territorial disputes, the International Court of Justice (ICJ) looks first to treaty law, then to uti possidetis, and finally to effective control. Treaties in relation to the territorial dispute play a preliminary or even preferential role for international dispute mechanisms in deciding territorial sovereignty.
The 1895 Treaty of Shimonoseki after the Sino-Japanese War is the starting point to examine the applicable treaties concerning the dispute. Japan’s official documents such as Minister Mutsu Munemitsu’s reply to Yasushi Nomura on January 11 of 1895 show that from the time of the fact-finding missions to Diaoyu Islands in 1885 to the occupation of the islands in 1895, Japan had consistently not made its moves to seize the Diaoyu Islands in public, until it defeated the Qing dynasty in the Sino-Japanese war. According to Article 2 (b) of the Treaty of Shimonoseki signed on April 17, 1895, the Qing court was forced to cede “the island of Formosa [Taiwan], together with all islands appertaining or belonging to the said island of Formosa” to Japan. Accordingly, the Diaoyu Islands were ceded to Japan as “islands appertaining or belonging to the island of Formosa.”
Following the Treaty of Shimonoseki, a series of treaties and international instruments after the World War II are the legal basis for China to claim its territorial sovereignty over the Diaoyu Islands. First, the Cairo Declaration of December 1943 proclaimed that “all the territories Japan has stolen from the Chinese, such as Manchuria, Formosa [Taiwan] and the Pescadores, shall be restored to the Republic of China. Japan will also be expelled from all other territories which she has taken by violence and greed.” The Diaoyu Islands, which were secretly stolen by Japan, should be returned to China.
Article 8 of the Potsdam Declaration of July 1945 reaffirms that “The terms of the Cairo Declaration shall be carried out” and the Japanese Instrument of Surrender of September 1945 reflect that the fact that Japan pledged to faithfully fulfill the obligations enshrined in the Potsdam Declaration. Japan’s obligation to return the Diaoyu Islands was further reinforced by these two legal documents.
Moreover, the Supreme Commander for the Allied Powers Instruction (SCAPIN) No. 677 of 1946 defined Japan’s administration power to “include the four main islands of Japan (Hokkaido, Honshu, Kyushu and Shikoku) and the approximately 1,000 smaller adjacent islands, including the Tsushima Islands and the Ryukyu Islands north of the 30th parallel of North Latitude.” The Diaoyu Islands, lying within 25°40′ – 26°00′ of North Latitude, were clearly not included into the regime defined by the SCAPIN No. 677.
Contrary to China’s approach to invoke the Treaty of Shimonoseki and legal documents such as the Cairo Declaration, Japan tends to deny the applicability of the Treaty of Shimonoseki in the dispute. Instead, Japan relies on multilateral treaties such as the 1951 San Francisco Peace Treaty, bilateral treaties such as the 1971 Ryukyu Transferring Agreement (“Agreement concerning the Ryukyu Islands and the Daito Islands with related arrangements,” i.e., the so-called “Okinawa Reversion Agreement”), as well as some decrees issued by the U.S. Ryukyu Administrative Government (which operated from 1950 to 1972).
Although Japan regards relevant provisions of the San Francisco Peace Treaty as the conventional basis for the Diaoyu Islands dispute, the applicability and legality of the Treaty are problematic. First, the negotiation, legislative, and ratification process of the San Francisco Peace Treaty in relation to the post-war arrangement with Japan excluded China and other allies such as the Soviet Union. Therefore, the legality of the San Francisco Peace Treaty as “peace treaty” or post-war arrangement is doubtful, since the said exclusion is a violation of the commitment by the allies to “cooperate with the Governments signatory hereto and not to make a separate armistice or peace with the enemies” which was envisaged in the 1942 Atlantic Charter. Second, according to the general rule of pacta tertiis nec nocent nec prosunt (treaty does not create obligations for a third party) under international law, China is not bound by the San Francisco Peace Treaty because of its status as a third party being excluded from the treaty signature.
Even if the San Francisco Peace Treaty is applicable in determining the dispute, if one examines the treaty provisions from the angles of the law of UN trusteeship and treaty interpretation, the use of terms in Article 3, such as “Nansei Shoto,” “any proposal of the United States to the United Nations to place under its trusteeship system,” and “powers of administration, legislation and jurisdiction” may not necessarily support Japan’s sovereign claims over the Diaoyu Islands.
Referring to the U.S. Civil Administration Proclamation No. 27 of December 1953, Article 1.2 of the “Agreed Minutes” attached to the Ryukyu Transferring Agreement included the Diaoyu Islands into the regime of the “Ryukyu Islands” by geographic coordinates which had been indicated in Proclamation No. 27. However, neither the 1971 Ryukyu Transferring Agreement nor Proclamation No. 27 of 1953 is a solid legal basis for Japan’s claim for several reasons.
First, such inclusion was defined by the form of “Agreed Minutes” instead of “Annex,” which had been required by the Japanese government during the negotiation. The legal form undermines the possibility of applying Article 1.2 of the “Agreed Minutes” in the dispute. Second, the Ryukyu Transferring Agreement violated the general rule of pacta tertiis nec nocent nec prosunt, since the Agreement has the effect of including the disputed territory (the Diaoyu Islands) into the Ryukyu Islands. Third, Proclamation No. 27 of 1953, which neither conforms with SCAPIN No.677, nor abides by the law of military occupation, shall not be regarded as a “legal basis” for the Ryukyu Transferring Agreement.
To maintain its claim, Japan disregards the Treaty of Shimonoseki and treaties signed among allies to maintain world peace and order after World War II. On the other hand, Japan relies heavily on the San Francisco Peace Treaty, the Ryukyu Transferring Agreement, and the decrees of the U.S. Ryukyu Administrative Government. Moreover, rules of territorial acquisition (such as “terra nullius” and “acquiescence”) are quoted frequently by the Japanese government. However, the ICJ normally follows the Tripartite Hierarchy Rule for the territorial dispute; namely, treaties in relation to the territorial dispute — instead of rules of territorial acquisition — will play a preferential role for the Court to examine the dispute. In deciding the Diaoyu/Senkaku Islands dispute, multiple considerations such as treaties and the factor of “critical date” (the point of time falling at the end of a period within which the material facts of a dispute are said to have occurred) are more decisive than acquiescence.
LIU Dan is Associate Research Professor at Koguan Law School, Shanghai Jiao Tong University.