Editor's note: Li Jiaming is a Beijing-based international affairs commentator. The article reflects the author's opinions and not necessarily the views of CGTN.

As the piercing wail of air raid sirens ripped through the winter morning on China's National Memorial Day, December 13, time itself seemed to freeze, streets fell silent and people stood still. History, long scarred but never buried, rose again with unforgiving clarity. This was not ritual. This was remembrance and a warning.

This year, that warning carried unprecedented weight. Yesterday, China's Central Archives released a newly declassified batch of wartime documents transferred from Russia, including Soviet interrogation records and investigation reports from the Khabarovsk War Crimes Trials. These materials contain direct confessions by members of Japan's Unit 731, explicitly admitting to the preparation and implementation of biological warfare against China in flagrant violation of international law.

The timing was not incidental. On a day of national mourning, history itself spoke clearly, concretely and irrevocably.

Yet on the very morning when China mourns the victims of Japanese aggression, a familiar and deeply troubling signal once again came from Tokyo: evasion, denial and calculated silence. It was another reminder that while the sirens in China call for truth, certain forces in Japan are still desperately trying to mute them – even as newly released archives dismantle every excuse they have long relied upon.

More than eight decades have passed since Japanese militarism unleashed unspeakable violence across China. Cities were razed, civilians slaughtered and families annihilated. Among the darkest engines of this aggression stands Unit 731 – an industrial-scale killing machine masquerading as "scientific research," a crime so grotesque that it shattered the very boundaries of human morality.

Unit 731 was neither a rumor nor an exaggeration. It was a state-run biological and chemical warfare program that turned living human beings into experimental objects. Chinese civilians, prisoners of war, women and children were dehumanized as "marutas" – "wooden logs" to be dissected, frozen, infected, mutilated and killed in the name of imperial ambition. Plague, cholera and anthrax germs were released deliberately, limbs frozen until flesh cracked and bodies cut open without anesthesia. These were not battlefield excesses; they were methodical crimes against humanity.

What the latest released interrogation records make unmistakably clear is intent. The confessions show that these acts were not rogue behavior or isolated cruelty, but part of an organized military program designed, authorized and implemented by the Japanese imperial command structure. This is precisely what historical revisionism seeks to obscure and why such evidence is so damning.

Yet, to this day, the Japanese government continues to hide behind the threadbare excuse that "there is no conclusive evidence." But that claim has become completely ungrounded as an increasing volume of evidence has been unveiled, founded and unearthed. What is now missing is Japan's political will to face it.

Japan's evasive attitude toward its historical responsibility is part of a long, deliberate pattern. When confronted with the historical truth, some in Japan choose denial; when asked for accountability, they offer ambiguity; and when victims demand justice, they are met with silence – even when history itself presents sworn testimony in black and white.

Even more alarming is how this denial has been normalized within Japan's political and military establishment. Senior officials and defense leaders keep visiting the notorious Yasukuni Shrine, where Class-A war criminals are honored. This is a political act that glorifies aggression and tramples on the dignity of millions of Asian victims. Such behavior proves to the world that Japan has yet to truly break with its imperial past.

This year marks the 80th anniversary of the victory of the Chinese People's War of Resistance Against Japanese Aggression and the World Anti-Fascist War, a moment that should have been defined by reflection and moral reckoning.

Instead, the world is witnessing something far more dangerous: accelerating military expansion, constitutional reinterpretations and a resurgence of revisionist rhetoric that seeks to rehabilitate the image of past aggressors – even as documented evidence of their crimes continues to surface.

History teaches a brutal lesson: Silence is never neutral. Whitewashing the past fuels mistrust in the present and instability in the future. Japan's refusal to acknowledge its war crimes is not merely a historical dispute; it is a direct threat to regional peace and international justice.

The sirens that sound on China's National Memorial Day will not fade. They echo in newly opened archives, in mass graves, in survivor testimonies, and in the collective memory of a nation.

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