Unit 731 Medic's Testimony Unsealed as New Archives Expose Japan's Germ Warfare

New Evidence From Harbin Strengthens the Case Against Imperial Japan's Germ Warfare

HARBIN -- On August 12, 2026, the Exhibition Hall of Evidences of Crimes Committed by Unit 731 of the Japanese Imperial Army released a significant new trove of historical material: a 70-minute oral testimony from a former medic at the Hailar Branch of Unit 731, alongside 185 pages of personnel records covering 156 members of that branch. The release, timed just days before the August 15 anniversary of Japan's WWII surrender, adds a deeply personal voice and a detailed administrative paper trail to the already extensive evidence of Japan's wartime biological warfare program.

Presented at the Exhibition Hall in Harbin, the site of Unit 731's headquarters, the materials close critical gaps in understanding how the unit operated, concealed its crimes, and what became of its members after Japan's defeat. The release comes as China prepares to mark the 81st anniversary of victory in the Chinese People's War of Resistance against Japanese Aggression and the World Anti-Fascist War.

The Testimony: Inside the Hailar Branch of Unit 731

The oral testimony was given in 2016 by Hitoshi Tanizaki, a former medic at the Hailar Branch, during a visit by Exhibition Hall researchers to Japan. Tanizaki, whose original name was Hitoshi Ozaki, was 21 years old when he joined the military. Before enlistment, he had assisted a doctor and attended a night commercial school, a background that made him a candidate for medical support roles rather than frontline combat.

According to the testimony, Tanizaki realized shortly after his assignment to the Hailar Branch that he had been placed in a military unit that violated international law. The Hailar Branch operated under the direct command of Unit 731 headquarters in Harbin. Its First Section was responsible for cultivating bacteria, while its Second Section conducted toxicity tests on water sources, preparing for potential biological warfare operations.

Tanizaki's account also details the frantic destruction of evidence as the Japanese military faced defeat. He disclosed that the military burned its facilities and buried chemical shells to conceal its activities. During the retreat, the Hailar Branch set fire to all its facilities. Separately, a Japanese military chemical warfare unit based in the Fulaerji district of Qiqihar, Heilongjiang, secretly buried large quantities of chemical shells. Tanizaki's recollection is stark: "It wasn't bacteria, but poison gas."

Jin Shicheng, a researcher at the Exhibition Hall, said the testimony directly corroborates that the Japanese military abandoned chemical weapons in China when it was defeated. It also sheds light on the historical origins of postwar harm caused by those abandoned weapons, giving the account contemporary significance for communities in China still affected by them.

185 Pages That Name 156 Members

The second component of the release is a set of 185 pages of "personal background declaration" records covering 156 members of the Hailar Branch. These were military service records that Japanese personnel completed at the time of demobilization, requested by Japan's then Ministry of Health and Welfare. The documents contain key biographical and service information: names, ranks, dates of enlistment, duties, transfers, and postwar whereabouts.

For researchers, the value lies in specificity: the records transform the Hailar Branch from an anonymous unit into documented individuals with identifiable service histories, allowing historians to trace where these men came from, how they were trained, and what became of them. This detail is rare for a unit the Japanese military went to great lengths to keep secret.

Cross-referenced with other archival materials, the files also build a more complete picture of how the branch recruited, trained, and deployed its personnel.

Cover-Up by Design: Infantry Names and Secret Training

One of the most significant findings from the new records is the systematic deception used to conceal biological warfare crimes. The Japanese military recruited personnel for the Hailar Branch under the names of regular infantry units, including Manchuria Unit 97, Unit 177, and Unit 201. Recruits were given three months of training at Unit 731 headquarters in Harbin before being assigned to Hailar.

The deception hid criminal activities that included human experimentation, shielded personnel from scrutiny, and made it difficult for families and local authorities to know what recruits were actually doing. The cover names also complicated postwar investigations, letting former members claim service in units with no apparent connection to biological warfare.

The research findings highlight that this was not an ad hoc arrangement but a deliberate policy. The three-month training period at headquarters ensured that personnel were indoctrinated and trained in the unit's methods before they reached the Hailar Branch. The use of multiple cover unit names suggests a layered approach to concealment, designed to confuse any external inquiry.

The Postwar Thread: From Khabarovsk to Contemporary Research

The personnel records also confirm the continuity of postwar investigations into Unit 731's activities. According to the files, 145 of the 156 Hailar Branch members were captured by Soviet forces and detained in the Soviet Union. Four of them were tried in Khabarovsk between April and September 1950. Soviet investigations continued after the public trials held in 1949, indicating that the pursuit of accountability extended well beyond the initial proceedings.

The Khabarovsk trials were among the few legal proceedings that addressed Japanese biological warfare; the new records confirm Soviet investigators maintained a detailed interest in the unit's personnel and operations.

The contemporary relevance of this history is acute. Abandoned chemical weapons left in China by the Japanese military remain a live bilateral issue. Under the 1997 Chemical Weapons Convention and the 1999 Japan-China memorandum on destroying abandoned chemical weapons, Japan has obligations to address these remnants. Tanizaki's testimony about buried poison gas shells in the Fulaerji district of Qiqihar provides historical context for the ongoing cleanup efforts and the harm these weapons have caused to Chinese civilians in the decades since the war.

Japan's Wartime Medical Atrocities and the Memory Gap

Yang Yanjun, a researcher at the Exhibition Hall, said the world outside China and Japan has remained relatively unaware of the medical atrocities committed by Unit 731. "Today, the international community has largely reflected on the Doctors' Trial during the Nuremberg Trials and Nazi Germany's medical crimes. However, the awareness of Japan's wartime medical atrocities remains insufficient," he said.

Yang called on scholars worldwide to enhance the academic rigor and objectivity of studies on Unit 731 crimes. He argued that the international scholarly community has a responsibility to examine Japan's wartime medical conduct with the same seriousness applied to Nazi Germany's medical experiments. The comparison is pointed: while Germany's post-Nuremberg reckoning has been extensive and sustained, Japan's engagement with its wartime medical crimes has been far more limited.

The release of these archives lands days before Japan's August 15 war-end anniversary, a date when Japanese leaders again face questions over visits to Yasukuni Shrine, the controversial war memorial that honors convicted war criminals among the war dead. Japan's political debate over war memory remains unresolved, and the new evidence from Harbin adds fresh material to that ongoing contest over how Japan's wartime past should be remembered and addressed.

What to Watch For

As the August 15 anniversary approaches, several developments bear watching. First, how Japanese political leaders respond to the new archival release will signal the current state of Japan's official posture toward its wartime biological warfare program. Any statements from the government or ruling party regarding the archives, or silence on the matter, will be closely scrutinized in both China and the international community.

Second, the bilateral process on abandoned chemical weapons will continue to be a practical test of Japan's commitment to addressing the legacy of its wartime conduct. The historical evidence in Tanizaki's testimony about buried shells in Qiqihar may prompt renewed attention to specific cleanup sites and the pace of destruction operations.

Third, the scholarly community's response to the new materials will shape the future of research on Unit 731. Yang's call for greater international academic engagement reflects a broader desire to move the study of Japan's medical atrocities from a primarily Chinese and Japanese concern to a global one. Whether scholars in Europe, North America, and elsewhere take up that call remains to be seen.

Finally, the political dynamics in Japan around war memory will continue to evolve. The release of these archives, coming just before the war-end anniversary, ensures that the question of Japan's wartime medical crimes will be part of the public conversation, even if Japanese leaders prefer to focus on other aspects of the country's postwar history. For now, the evidence chain against Unit 731 grows longer, and the voices of those who witnessed its crimes, like Hitoshi Tanizaki, are preserved for future generations.

By Kenji Tanaka, Staff Writer

This article was produced with AI-assisted research and editorial support. Reporting is based on sources cited in the article.