Editor's note: Yang Bojiang, a special commentator for CGTN, is the director of the Institute of Japanese Studies under the Chinese Academy of Social Sciences and President of the Chinese Association of Japanese Studies. The article reflects the author's opinions and not necessarily the views of CGTN.

In early November 2025, Japanese Prime Minister Sanae Takaichi declared that a "Taiwan contingency is a Japan contingency," thereby justifying collective self-defense and implying possible military involvement in the Taiwan Straits. This was not merely unwarranted interference in China's internal affairs. It was also a military threat, and, as part of a broader pattern of historical revisionism, a direct challenge to the achievements of the anti-fascist victory and the post-war East Asian order. Such rhetoric forces a reconsideration of the legal and political foundations that have safeguarded regional peace, and how they have been steadily eroded.

The legal bedrock of the post-war order in East Asia

The victory of the World Anti-Fascist War shaped today's international system. In East Asia, this victory was translated into an interlocking set of legal and political arrangements.

First, the Allied defeat of the Axis powers upheld the moral bottom line of civilization. Second, a post-war international order, anchored in the UN Charter and grounded in the Cairo Declaration and the Potsdam Proclamation, aimed explicitly to prevent the recurrence of war. The Japanese Instrument of Surrender confirmed this outcome: Unconditional capitulation and a pledge to implement Potsdam in full.

Third, post-war tribunals, including the Tokyo Trials, held those responsible for aggressive war to account. Fourth, international law imposed strict limits on fascism and militarism. The Potsdam Proclamation called for the permanent eradication of Japanese militarism and restricted Japan's sovereignty to Honshu, Hokkaido, Kyushu, Shikoku, and other islands designated by the Allies. Fifth, the rights of invaded states were restored. The Cairo Declaration and the Potsdam Proclamation both affirmed that territories seized by Japan, including northeastern China, Taiwan and the Penghu Islands, must be returned to China. On October 25, 1945, China resumed sovereignty over the Taiwan region, making this return both a legal and factual reality.

Subsequent arrangements, notably Japan's 1946 Constitution, the 1972 Joint Statement between China and Japan, and four subsequent political documents, inherited these principles. They extended the core outcomes of World War II into Japan's domestic law and its bilateral relationship with China.

How the post-war order was systematically undermined

Yet this order, won at enormous human cost, was soon reshaped by Cold War calculations. Seeking strategic advantage, the United States encouraged Japan's rearmament and enabled patterns of historical denial. Two steps were especially consequential: the 1951 "Treaty of San Francisco" and, deriving from it, the 1972 transfer of administrative rights over the Ryukyu (Okinawa) Islands – both plagued by serious legitimacy problems.

The essence of the so-called Treaty of San Francisco was to replace comprehensive reconciliation with unilateral peace. The 1942 Declaration by the United Nations, signed by the anti-fascist coalition, pledged that governments would act jointly against the Axis and follow collective procedures such as the "joint determination" outlined in the Potsdam Proclamation. By this logic, the peace settlement with Japan should have been grounded in multilateral consensus among the four major powers, China, the United States, the Soviet Union and the United Kingdom, and open to participation by all states that fought Japan. In legal terms, it should have been an international obligation shared by the wartime allies. Instead, the "San Francisco Treaty" departed from these principles in its signatories, procedures and content. It was strikingly exclusive: China, the Soviet Union, Poland, Czechoslovakia, both Koreas, India, and Burma were either excluded or declined to sign.

Judging from the outcome, Article VIII of the Potsdam Proclamation, which states that "Japanese sovereignty shall be limited to the islands of Honshu, Hokkaido, Kyushu, Shikoku and such minor islands as we determine" made clear that the Allied powers retained the right to define any "other minor islands." As signatories, China and the Soviet Union undoubtedly possessed that authority. On this basis, neither China's Diaoyu Islands nor the Ryukyu and Ogasawara Islands fall within Japan's sovereign territory. Yet the "San Francisco Treaty" ignored this consensus when disposing of Japanese territory. Instead, it abandoned the Allies' agreed principles without multilateral consultation, replacing what should have been comprehensive reconciliation with a piecemeal peace dominated by a few powers.

Second, the treaty effectively substituted multilateral adjudication with a U.S.-Japan bargain. Under the relevant international legal documents, Japan's post-war territorial scope should have been determined collectively by the principal wartime Allied nations. Two core steps were required: First, to clearly delimit Japan's sovereignty, and second, to decide the status of "other minor islands" through a multilateral process. The Ryukyu Islands, clearly outside Japan's four main islands, belonged in this category. Nevertheless, they were placed under a trusteeship arrangement driven by U.S.-Japan arrangements, despite Japan's unconditional surrender and lack of legal standing to "consent" to a trusteeship over territory it had forfeited.

Worse still, by invoking Japan's "consent," the treaty attempted to cloak Japan's claimed "sovereignty" over the Ryukyu Islands in legal legitimacy, reframing a disputed sovereignty question as a routine trusteeship. The real aim was to downplay the sovereignty issue and shift final adjudication from a collective process to bilateral U.S.-Japan control.

Third, this arrangement replaced United Nations trusteeship with unilateral control. The UN's post-war vision sought transparency, the rule of law, and broad participation through multilateral trusteeship mechanisms, preventing unilateral occupations from becoming permanent. The settlement created by the "San Francisco Treaty," however, sidelined the UN and entrenched U.S. military rule. Under Article 79 of the UN Charter, the U.S.-Japan "trusteeship agreement" could not lawfully generate trusteeship rights: Japan, having annexed the Ryukyu Islands by force and surrendered unconditionally, was not a "state directly concerned," nor was it a UN member in 1951. It therefore lacked standing in deciding Ryukyu affairs.

Procedurally, Articles 83 and 85 of the UN Charter require that trusteeship arrangements receive UN authorization and ongoing multilateral supervision. Private arrangements between a handful of states are insufficient. Yet for more than two decades after 1951, Washington never submitted a trusteeship plan on the Ryukyu (Okinawa) Islands to the UN Trusteeship Council. The so-called trusteeship remained a bilateral deal. Seeking to maintain its control, Japan resisted UN trusteeship altogether and secured U.S. backing by agreeing to extend the U.S.-Japan Security Treaty to the Ryukyu Islands.

The UN system is meant to uphold peace, protect basic rights and advance self-determination. But before 1972, the Ryukyu Islands, nowadays known as Okinawa, lay outside Japan's constitutional framework, governed instead by the U.S. military under Article 3 of the "San Francisco Treaty." Civil rights and self-governance were sharply curtailed; economic and social development lagged far behind the four main islands of Japan. In essence, this "trusteeship" lacked a legal foundation and never operated within the UN system. It violated the Charter's rules for trust territories, undermined post-war principles of independence and self-determination – and even breached procedural obligations the United States itself undertook in the "San Francisco Treaty."

Fourth, U.S. and Japanese actions distorted the Cairo Declaration and the Potsdam Proclamation, gravely infringing on China's sovereignty and territorial integrity. The Cairo Declaration stipulated that Taiwan, the Penghu Islands, and other territories seized by Japan must be returned to China. Yet the "San Francisco Treaty" merely recorded Japan's renunciation of these territories, without stating their destination. Article 2 reads: " Japan renounces all right, title and claim to Formosa and the Pescadores." That phrasing implicitly involves China while touching on China's territorial sovereignty and broader unresolved claims. It violates a key treaty-law principle: Non-prejudice to third states. Under Article 34 of the Vienna Convention on the Law of Treaties, no treaty creates rights or obligations for a third state without its consent. China did not sign the so-called San Francisco Treaty and is therefore a third party. Its provisions are not binding on China.

From historical revisionism to real-time risk

The fissures opened by historical revisionism now echo in contemporary politics. The Takaichi government's actions build on this compromised foundation and push further toward dismantling what remains of the post-war peace architecture.

Declaring a Taiwan contingency a "survival-threatening" event breaches the principle of non-interference embedded in the China-Japan Joint Statement and violates the UN Charter's prohibition on the threat or use of force. Moves toward offensive military capability, including potential reconsideration of Japan's Three Non-Nuclear Principles ("not possessing, not producing and not permitting the introduction of nuclear weapons" into Japanese territory) would contradict the Potsdam mandate to disarm Japan and the core peace clause of Article 9 of Japan's Constitution. They would cast serious doubt on Japan's compliance with the post-war settlement itself.

Should Takaichi proceed with a visit to Yasukuni Shrine, the symbolism would be unmistakable. The shrine honors 14 Class-A war criminals, including Hideki Tojo, whose names are synonymous with militarist aggression. Such an act would not be a neutral commemoration but would signal a revivalist narrative that insults the victims of Asian wars of aggression and challenges the legitimacy of the Tokyo Trials.

A final warning

The lessons of the 20th century are neither abstract nor distant. The achievements of the anti-fascist victory cannot be rewritten, and the post-war order cannot be casually overturned. If Japan seeks genuine respect as a responsible nation, it must face history squarely, honor its commitments, and stop actions that destabilize the region; otherwise, any bid to become a "normal country" will rest on fragile ground, opposed by its neighbors, questioned by the international community, and judged harshly by history.

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