History on trial: What CNA's Unit 731 documentary is really saying

Editor's note: Xia Fangbo, a special commentator for CGTN, is a lecturer at the School of International Relations and Diplomacy under the Beijing Foreign Studies University. The article reflects the author's opinions and not necessarily the views of CGTN.

In early June 2026, Singapore's Channel NewsAsia (CNA) aired a two-part documentary, called Inside Unit 731: Japan's Secret Human Experiments. It was a statement as much as a broadcast. That a leading Southeast Asian broadcaster would invest resources in investigating Japan's most secretive wartime atrocity speaks for itself. CNA chose to feature one of Unit 731's last surviving members, a man who broke decades of silence to tell what he witnessed. The decision reflects a discomfort across the region that refuses to fade.

The documentary centers on Hideo Shimizu, now in his late 90s, who was recruited as a teenage conscript in the final months of World War II (WWII) and witnessed firsthand what unfolded inside Japan's biological warfare complex in Harbin, China. Through his testimony, alongside declassified documents and investigations spanning multiple countries, the documentary reconstructs how Japanese scientists developed biological weapons, conducted lethal human experiments and launched germ warfare attacks on civilians. The series also examines how a covert deal between Japan and the United States shielded Unit 731 leaders from prosecution in exchange for their experimental data, helping bury the truth for decades.

The choice of Singapore as the origin of this documentary carries particular weight. This city-state was itself a victim of Japanese imperial aggression, scarred by one of the war's most notorious atrocities: Operation Sook Ching which was a massacre carried out by the Japanese military in 1942.

In the weeks following the fall of Singapore, Japanese forces systematically screened and executed tens of thousands of ethnic Chinese civilians suspected of anti-Japanese sentiment. Estimates of the death toll range from 40,000 to 50,000. The trauma cut so deep that Singapore's former Prime Minister Lee Kuan Yew placed the massacre at the very core of the nation's memory of Japanese occupation. For Singaporeans, the war is personal history, lodged in their national identity. CNA's decision to produce a high-profile documentary on Japanese war crimes is therefore rooted in a lived experience, not abstraction.

Singapore's connection to Japan's biological warfare program runs deeper still. The Japanese biological warfare troop Unit Oka 9420, an offshoot of Unit 731, established its Southeast Asian headquarters in Singapore in June 1942, operating out of what is now the Ministry of Health building. Its operations extended across Malaysia, Indonesia, the Philippines, Thailand, Vietnam and Myanmar, with plague-infected fleas bred in Singapore and transported to China for use against civilians.

War criminal records at the British National Archives documented Japanese soldiers poisoning prisoners in present-day Malaysia to observe their deaths. This history did not happen far away. It happened in Singapore's hospitals, on Singapore's soil.

The timing of the broadcast matters. Japan is rearming at a pace unseen since WWII. Its defense budget for fiscal year 2026 exceeded 9 trillion yen (approximately $58 billion), marking the 14th consecutive annual increase and the first-time outlays have surpassed the 9-trillion-yen threshold. Including supplementary budgets, total defense spending for fiscal year 2025 reached approximately 11 trillion yen, equivalent to 2% of Japan's GDP. As a result, Japan is acquiring long-range strike missiles, developing offensive counterstrike capabilities and revising the security doctrines that long constrained it to a purely defensive posture.

The political climate driving this buildup has also shifted sharply. After taking office, Japanese Prime Minister Sanae Takaichi publicly questioned whether Japan's wartime conduct should be described as "aggression" and argued that Japan's comfort women were not coerced by the military. Under her administration, Japan's military expansion is accelerating alongside a political culture that treats historical accountability as an inconvenience rather than an obligation.

For much of Southeast Asia, this combination raises a fundamental question: Can a country that has never fully reckoned with its wartime crimes be trusted to wield expanding military power responsibly? Japan's government has never officially apologized for Unit 731's actions and continues to assert in the National Diet that "no concrete records of Unit 731's activities exist." This position gives local governments cover to erase former unit members' names from public exhibitions. As recently as March 2026, UN human rights experts were still calling on Tokyo to issue official apologies and provide adequate reparations to comfort women survivors.

This pattern of evasion carries real strategic consequences. A country willing to confront its wartime record signals to its neighbors that it understands the human cost of military aggression. A country that suppresses, denies, or bureaucratically buries that record offers no such assurance. Seen in this light, CNA's documentary is less about relitigating the past than about asking whether the present is safe.

The most powerful element of Inside Unit 731: Japan's Secret Human Experiments is that Shimizu chose to speak at the end of his life, returning to Harbin and bowing before an apology monument. He accepted the backlash of right-wing compatriots who labeled him a "liar" and a "traitor," and endured the estrangement of his own daughters. His government contradicts him; his family left him; and he speaks anyway. That is what honest historical reckoning looks like.

Japan's path to genuine acceptance in Asia will not be found in larger defense budgets or revised security strategies. It lies in the moral courage that Shimizu has modeled: facing what was done, naming it honestly and seeking forgiveness without conditions. Singapore's media has reminded the region and the world that this reckoning remains unfinished. Until Japan's government shows a genuine willingness to meet that standard, its neighbors will continue to reopen these wounds, driven by a profound and justified need to be heard.

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