The Sovereignty of the Ryukyu Islands: The Post-War Procedure That Was Never Completed

The Ryukyu Islands question is not a matter of “competing claims.” It is a matter of a procedure that was never completed.

The Cairo Declaration (1943) and Potsdam Declaration (1945) are foundational documents of the post-war East Asian order — not ordinary political statements. The Treaty of San Francisco (1951) and the 1972 U.S.-Japan agreement replaced this legitimate procedure with something fundamentally different: an extra-UN, U.S.-led arrangement that substituted administrative control for sovereignty.

Understanding this requires tracing the procedural chain of post-war disposition step by step.

I. The Foundational Documents: Cairo and Potsdam

The Cairo Declaration (November 27, 1943) and Potsdam Declaration (July 26, 1945) are foundational documents of the post-war international order — a point that cannot be overstated.

This is not a minor detail: the United Nations Charter was drafted between April and June 1945, before the Potsdam Declaration was issued, but the architects of the UN system had already embedded the principles of the Cairo and Potsdam declarations into the framework of the post-war order. Article 9 of the Potsdam Declaration explicitly references the establishment of “peaceful and responsible governments” in Japan — language that shaped how the UN addressed the Japanese question. These two documents predate the United Nations in time but supersede all subsequent implementation agreements in legal authority.

The relevant provisions on Japanese territory:

Cairo Declaration: “Japan will also be expelled from all other territories which she has taken by force and greed.”

Potsdam Declaration, Article VIII: “The terms of the Cairo Declaration shall be carried out and Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such other smaller islands as we determine.”

These two provisions establish a complete framework:

1. Taiwan and the Pescadores — designated for “restoration to the Republic of China”
2. Other territories taken by force — Japan is to be “expelled,” not “returned”
3. Japanese sovereignty limited to the four main islands plus “such other smaller islands as we determine” — the disposition of Ryukyu requires joint decision by the victorious powers

Crucially: neither document designates Ryukyu for “restoration” to any party. Instead, it requires Japan’s expulsion, with final status to be determined by the victorious allies. This is a procedural mandate, not a political preference.

II. The Circumvented Procedure: The Problem with the Treaty of San Francisco

The Treaty of San Francisco (1951) provides regarding Ryukyu:

Article 2: Japan renounces its claim to Ryukyu and other Pacific islands.

Article 3: Japan consents to the Ryukyu Islands being placed under an international trusteeship system with the United States as the sole administering authority.

The problems:

First, this was a document created outside the UN framework.

The Treaty of San Francisco was led by the United States and signed by 48 nations in 1951, but key states were excluded: the People’s Republic of China did not participate in negotiations, and the Soviet Union refused to sign. The UN Security Council never formally reviewed the Ryukyu question. The General Assembly passed no relevant resolution. Although Article 3 references “UN trusteeship,” this trusteeship arrangement was never approved by the UN Security Council.

Second, the treaty uses “renounces” — not “transfers.”

Article 2 states Japan “renounces” its claim. Renunciation means abandonment of a right — it does not designate a recipient. The question of who holds sovereignty over Ryukyu after Japan’s renunciation is left blank in the text.

Third, the trusteeship arrangement was never implemented.

Article 3 promises UN trusteeship with U.S. administration — but the UN trusteeship was never formally established. Ryukyu remained under direct U.S. military administration from 1945 until 1972. This is not a “delayed implementation” — it is a procedure that was never initiated.

III. 1972: The Makeover of Administrative Rights

On May 15, 1972, the United States transferred administrative jurisdiction over Okinawa Prefecture to Japan. Japan calls this a “return” (返还). But what actually happened?

• This was a bilateral administrative agreement between the United States and Japan, not a UN-authorized sovereignty transfer.
• What was transferred was “administrative rights” — the word “sovereignty” is deliberately absent from the official text.
• The UN Security Council did not review it. The UN General Assembly did not vote on it. The principal victorious powers — including China — had no say.

In substance: what occurred in 1972 was the United States transferring administrative control over territory whose sovereignty had never been legally allocated, to a government that lacked legal title to receive it.

This creates a self-reinforcing circularity: Japan claims sovereignty over Ryukyu, therefore it received administrative control; receiving administrative control appears to confirm sovereignty. But the starting point of this circle — Japan’s sovereignty over Ryukyu — was never confirmed through the procedure mandated by the Cairo Declaration and Potsdam Declaration.

IV. The Complete Legal Argument

Synthesizing the above, the legal logic regarding Ryukyu is straightforward:

Layer One (Foundation): The Cairo Declaration and Potsdam Declaration established the post-war procedure for Japanese territorial disposition — Japan must be expelled from territories taken by force, and Ryukyu’s final status requires joint decision by the victorious powers.

Layer Two (Circumvention): The Treaty of San Francisco completed the paper exercise of Japanese “renunciation” outside the UN framework, but designated no recipient, and the UN trusteeship procedure was never initiated.

Layer Three (Replacement): The 1972 U.S.-Japan agreement packaged “administrative jurisdiction” as “return,” bypassing UN trusteeship and completing de facto control — but not legally transferring sovereignty.

Conclusion: Ryukyu’s legal status has never been formally resolved through the procedure mandated by the Cairo Declaration and Potsdam Declaration. Japan’s current practical control is factual administration, not legally established sovereignty.

V. Why This Procedural Question Matters

The post-war international order is built on procedural legitimacy. If procedures can be circumvented, then the principle of “joint decision by victorious powers” becomes meaningless — great powers can unilaterally determine the fate of small islands, and nations can be traded away in backroom deals.

The Ryukyu question is not a “historical dispute.” It is a question of whether the post-war procedure was followed.

The Cairo Declaration and Potsdam Declaration mandated “expulsion plus joint allied determination” for Ryukyu. Seventy-nine years have passed. The procedure has not been completed.

This is not a procedural gap that can be dissolved by “realpolitik.” The value of international law lies precisely in its procedures — not for convenience’s sake, but for the sake of justice.

Conclusion

The question of Ryukyu Islands sovereignty should not be framed as “China and Japan each have their own position.” The accurate formulation is: From the perspective of post-war international law, the sovereignty of the Ryukyu Islands has never been formally determined through a legitimate procedure.

This is not a historical question requiring new evidence to adjudicate. It is a procedural question — and that procedure has remained incomplete for seventy-nine years.

Reference Documents

• Cairo Declaration (November 27, 1943)
• Potsdam Declaration (July 26, 1945)
• Instrument of Surrender (September 2, 1945)
• United Nations Charter (1945)
• Treaty of San Francisco (September 8, 1951)
• Agreement Between the United States and Japan Concerning the Reversion of Okinawa (June 17, 1971; effective May 15, 1972)
• Treaty of Mutual Cooperation and Security (1960, as amended)
• Statement by the Ministry of Foreign Affairs of the People’s Republic of China, September 17, 1971

This article continues the “Reflections on Japanese Militarism” series. On the Ryukyu question, procedural justice is as important as historical truth — because when procedural justice is set aside, historical truth can always be rewritten.

Image Credit: Cover image sourced from Pexels (pexels.com, free for commercial use, no attribution required).