Editor's note: Tang Yongliang is a researcher at the Institute of Japanese Studies, Chinese Academy of Social Sciences. The article reflects the author's opinions and not necessarily those of CGTN. 

　　The so-called undetermined status of Ryukyu, also referred to as the "undetermined sovereignty of Ryukyu," means that the sovereignty over the Ryukyu Islands remains disputed. 

　　The term has both a broad and a narrow sense. In the broad sense, the "undetermined status of Ryukyu" refers to the situation since modern times, where Ryukyu was illegally occupied by Japan without widespread recognition by the international community. To this day, the sovereignty issue remains unresolved. 

　　In the narrow sense, it refers specifically to the end of World War II, when the Cairo Declaration and the Potsdam Proclamation – documents concerning the post-war disposition of fascist Japan – explicitly delimited Japan's territorial scope, separated Ryukyu from Japan, placed it as a "potential trusteeship territory" and left its sovereignty legally unsettled to this day. 

　　The "undetermined status of Ryukyu" manifests not only in legal terms but also in social cognition, and changes in international relations likewise exert influence upon it. 

　　Historically, Ryukyu was an independent kingdom. Japan's modern annexation of Ryukyu was a unilateral act of violent seizure: no treaty regarding state sovereignty was concluded, no consent was obtained from China, the suzerain power, and the annexation contravened international legal norms on the acquisition of territorial sovereignty in the 19th century. 

　　In 1372, the Hongwu Emperor Zhu Yuanzhang of the Ming Dynasty (1368-1644) sent envoys to instruct the King of Chuzan of the Ryukyu Kingdom. King Satto submitted a memorial acknowledging vassal status. Subsequently, the polities of Sannan and Sanhoku also began tributary relations with the Ming Dynasty. The Ming Dynasty conferred seals, calendars and other symbols of investiture upon the three kings, thereby formally establishing the Ming-Ryukyu suzerain-vassal relationship. 

　　This relationship continued into the Qing Dynasty (1644-1911), during which Ryukyu remained a vassal state of China. In 1872, without the Ryukyu government's consent, Japan unilaterally "invested" King Sho Tai as the "Domain Lord of Ryukyu," abolished the Ryukyu Kingdom and turned it into the Ryukyu Domain under Japanese control. 

　　In 1874, using the killing of Ryukyuans in Taiwan as a pretext, Japan dispatched troops to Taiwan. In 1879, despite Ryukyuan resistance, Japan forcibly abolished the Ryukyu Domain, divided it into two parts – integrating the northern islands into Kagoshima Prefecture and renaming the remainder "Okinawa Prefecture" – in an attempt to sever Ryukyu's ties to China. Japan's unilateral actions faced opposition from both Ryukyu and China. 

　　In 1879, with mediation by former U.S. President Ulysses S. Grant, China and Japan had tentatively reached a Tripartite Ryukyu Partition Agreement involving China, Japan and Ryukyu. However, the Qing Dynasty (1644-1911) government ultimately refrained from signing it for various considerations. Thereafter, China and Japan conducted prolonged negotiations over the status of Ryukyu, but to no avail. 

　　From November 22 to 26, 1943, the leaders of China, the United States, and the United Kingdom convened the Cairo Conference in Egypt, during which they discussed the post-war disposition of Ryukyu. Although the issue was not ultimately written into the Cairo Declaration, the declaration's provision that "Japan will also be expelled from all other territories which she has taken by violence and greed" undoubtedly applied to Ryukyu. 

　　On July 26, 1945, the three nations issued the Potsdam Proclamation, urging Japan's unconditional surrender. It clearly stated that "the terms of the Cairo Declaration shall be carried out" and that "the Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine," thereby explicitly separating Ryukyu from Japanese territory. 

　　On September 2, 1945, aboard the U.S. battleship Missouri in Tokyo Bay, Japanese representatives signed the Instrument of Surrender, proclaiming to the world that the Japanese government, the emperor and the imperial general headquarters "accept the provisions of the Potsdam Proclamation and surrender unconditionally." Thus, the post-war disposition of Ryukyu formed an important part of the post-war international order. 

　　On January 26, 1946, the general headquarters of the Allied Forces issued Directive No. 677 to the Japanese government via the Central Liaison Office in Tokyo, explicitly requiring Japan to cease exercising governmental or administrative authority over the Ryukyu Islands south of 30 degrees north latitude. 

　　After the outbreak of the Cold War, the United States, excluding the People's Republic of China, the Soviet Union and others, forged a separate peace with Japan and signed the "Treaty of San Francisco," which to some extent diluted the explicit territorial provisions of the Cairo Declaration, the Potsdam Proclamation and the Instrument of Surrender, ambiguously expanding Japan's territorial scope (extending it one degree southward). Although the treaty nominally placed Ryukyu under a UN trusteeship, the United States never followed the trusteeship procedures. 

　　With the deepening of the Cold War, the U.S.-Japan alliance became increasingly intertwined; the United States gradually relaxed its restrictions on Japanese influence within the Ryukyu Islands, and in 1953 and 1968 unilaterally transferred administrative rights over the Amami Islands and the Nanpo Islands to Japan. 

　　In 1971, under pressure from the Vietnam War and the Ryukyuan anti-U.S. movement, the Nixon administration concluded the "Agreement Between Japan and the United States of America Concerning the Ryukyu Islands and the Daito Islands," again unilaterally transferring administrative rights to Japan on the condition that Japan allow continued U.S. military presence in the islands. 

　　These U.S.-Japan transfers of administrative authority were privately arranged, lacked approval from the United Nations and other Allied powers, and are illegal and invalid; they did not alter the undetermined nature of Ryukyu's sovereignty. 

　　After Japan's modern annexation of Ryukyu, it forcibly implemented assimilation policies, causing severe harm to the indigenous rights of Ryukyuans, while their political rights remained unresolved for a long time. 

　　Over the 80 years since the end of World War II, Okinawans' burden of hosting military bases has never substantially improved. Despite accounting for only 0.6 percent of Japan's land area, Okinawa hosts more than 70 percent of U.S. military facilities exclusively used by U.S. forces in Japan. 

　　As Nozato You, a former political commentator at the Ryukyu Shimpo and visiting professor at Hokuriku University, noted that the people of Okinawa have already reached the limits of endurance. In response, Okinawa has adopted comprehensive strategies of active resistance. On the one hand, it continues to apply pressure on the U.S. military and the Japanese government through prolonged anti-base movements and legal battles; on the other hand, it pursues internationalization, seeking support from global public opinion. 

　　In sum, the issue of U.S. military bases in Okinawa is not merely a problem for the United States, Japan and Okinawa; it concerns the post-war international order as a whole. At its core lies the issue of Ryukyu's sovereignty. 

　　The legitimacy of the U.S.-Japan handling of Ryukyu – constructed in disregard of the spirit of the Cairo Declaration, the Potsdam Proclamation and the Instrument of Surrender – remains questionable, and resolving the sovereignty question of Ryukyu requires continued attention from the international community.