Uncovering Japan’s Hidden Past: The Resurfaced Truth About Unit 731’s Germ Warfare Program and China’s Silenced Victims

As the 80th anniversary of Japan’s World War II surrender approaches, vestiges of the conflict persist, manifesting in unresolved wounds, ongoing disputes, newly unearthed artifacts, and lessons still to be learned.

This year, the disclosure of military documents from WWII has invigorated researchers delving into Japan’s notorious biowarfare program, active between 1936 and 1945. In China, a film depicting this dark chapter in history was unexpectedly delayed, sparking an online uproar.

Entitled “731 Biochemical Revelations” in English, the movie chronicles the plight of Chinese victims subjected to cruel medical experiments by Japan’s Imperial Army Unit 731.

When the screening was postponed and later rescheduled for September without explanation, some viewers speculated that authorities sought to avoid a potential conflict jeopardizing diplomatic relations between Beijing and Tokyo.

Liu Jiaying, an anchor at state-run Hunan Satellite TV, voiced concern in a social media video, asking “Should we choose to forget this part of history just because the movie exposes these scars? This film is not merely a retelling of the past but also a warning for the future.”

One of the last living witnesses capable and willing to discuss Unit 731 is Hideo Shimizu, now 95 and residing in Nagano prefecture. At age 14, he joined the Youth Corps of Unit 731 and was assigned to its headquarters in Japanese-occupied Northeast China in 1945, five months before the war’s end.

In an interview at his home, Shimizu recalled his surprise upon seeing doctors in white lab coats at the headquarters, unaware that he would be engaged in medical activities, let alone ones accused of dissecting live prisoners without anesthesia or conducting germ warfare against Chinese soldiers and civilians.

Shimizu recounted his first hint that something sinister was afoot when he was led into a room filled with human organs preserved in glass jars. The sight of a whole female body with a fetus in its womb left the deepest impression on him.

Stricken by illness after receiving a piece of bread from an older member of the unit, Shimizu believes that experiments were conducted on youth corps trainees like himself. As Japan’s defeat approached, Unit 731 personnel were ordered to destroy evidence and witnesses. “Maruta,” or logs—non-human beings—was how Unit 731 doctors referred to their test subjects, and Shimizu claims he never saw any of them alive.

Estimated to have caused the deaths of around 3,000 individuals, Japan’s government has yet to issue an apology for Unit 731’s actions, insisting that it has found no evidence of experiments on Chinese prisoners despite a Tokyo court ruling in 2002 confirming such experiments and biological warfare.

Last year, Shimizu traveled to China to express his remorse. His candor has drawn criticism from some quarters in Japan, while others, like Hideaki Hara, a former school teacher who curates an exhibit on Unit 731 at a local museum in Nagano, support him.

“When we discuss the war,” Hara notes, “it’s easier to focus on ourselves as victims, such as those affected by the atomic bombings. However, our role as perpetrators is often overlooked. People prefer not to talk about it.”

Katsutoshi Takegami, a 77-year-old resident of Nagano prefecture, has delved into his father’s military service after discovering a trunk belonging to him containing photographs depicting his service in Unit 1644, another branch of Japan’s biowarfare program.

In May, at the request of researchers, Japan’s national archives made public Unit 1644’s personnel rosters, which Takegami hopes to use to locate any surviving members of the unit.

Historians have uncovered a network of units spanning from Unit 731 in the north to Unit 8604 in Guangzhou and down to Unit 9420 in Singapore, each adapting to local conditions to create biological weapons and spread diseases such as plague and malaria among enemy troops.

With euphemistic names like “anti-epidemic and water supply” units, their mission was twofold: maintaining the health of Japanese troops while compromising that of their adversaries.

After the war, an international tribunal known as the Tokyo Trial sentenced seven Japanese officials to death for war crimes. However, Unit 731’s leaders returned to Japan, where many went on to hold prestigious positions in medical institutions and pharmaceutical companies.

This was possible due to a deal struck between the U.S. and Unit 731 leaders: immunity from prosecution for their war crimes in exchange for access to the unit’s medical research data. The U.S. government maintained secrecy over Unit 731 and the terms of the agreement for decades.

Cambridge University professor Barak Kushner points out that a similar arrangement was made with German scientists, including former Nazi party members, who were granted immunity in exchange for their contributions to U.S. missile and space programs under “Operation Paperclip.”

In Japan, the U.S.’s priority during this period was rebuilding the country as a bulwark against communism, according to Kushner. The deal offered in these circumstances reflected the political climate and the limitations of justice for war crimes in the immediate post-war era.

It represented one instance where American ideals of justice took a back seat to self-interest and national security concerns.