In the Unit 731 Museum, a full-size panorama depicts the Japanese initial attempt to spread cholera downstream; dilution made the strategy impractical and inspired Shiro to use insects to target victims with disease.
Content warning: This article contains descriptions of violence, including murder, medical torture, and other abuse of prisoners during wartime.
Say “qī sān yī” (“seven-three-one”) to Chinese students and any smiles will go away.
“Yes, that was terrible,” they will respond.
They are referring to the major Japanese biological warfare unit in northeast China, Unit 731, that committed horrible atrocities from 1932 until the end of the Second World War. In 2015, the Unit 731 Criminal Evidences Museum was modernized. I visited this memorial in 2016.
The head of Unit 731 was Ishii Shiro (1892–1959), a Japanese medical doctor charged with developing bioweapons. Such tactics had been declared a war crime by the Geneva Conventions, and Japan had been one of 38 signatories (Geneva Protocol 1925). But to the Imperial Japanese generals in an era of ultra-nationalism, that meant that biowarfare must be very effective. They accepted Ishii’s argument “that biological warfare must possess distinct possibilities, otherwise, it would not have been outlawed by the League of Nations” (Gold 1997).
Initially located in the city of Harbin in northeastern China, the unit’s biowarfare work was deemed too publicly visible. To maintain research secrecy, they built a bioweapons lab about 100 kilometers south of Harbin at Zhongma Fortress. It was the site of the small village of Beiyinhe, which was forcefully evacuated. Prison cells and medical labs were built by Chinese workers, who were then killed to hide the function of the fortress. It could hold up to 1,000 prisoners but usually operated at half that capacity. Prisoners were well fed in order to provide reliable results for experiments, but the average life of a prisoner was only one month. While some experiments merely tested how long prisoners could survive without water, other work focused on immunization from agents that could be used in biological warfare. This required the culturing of “better” biowarfare agents, and thus became the thrust of Ishii Shiro’s work.
Some prisoners managed to escape, risking exposure of the nature of the research at Zhongma Fortress, and it was closed in 1937. However, Japan’s military leadership had become even more convinced that biological weapons could be effective and even critical against a possible invasion of Soviet forces from Siberia. Ishii’s operations were moved to an even larger facility built at Pingfang in 1938, 33 kilometers south of Harbin. Today, it is a suburb of Harbin and the site of the newly renovated museum built on top of the remains of this prison and research facility. This new museum is built in a modern design somewhat similar to the War Memorial Museum in Nanjing. But unlike the Nanjing museum, where visitors are followed by mournful music, the collection of artifacts and photographs at Unit 731 are too tragic to need reinforcement. Earphone sets provide narration in Chinese, English, or Japanese, and the narrative transitions as you move from room to room.
The Unit 731 site was partially destroyed to eliminate evidence.
Over 30 disease-causing agents were studied for military use, including cholera, anthrax, typhoid, salmonella, bubonic plague, and typhus. Unit 731 grew large vats of cholera bacteria, a water-borne disease that causes death by diarrhea and dehydration. One museum panorama shows Japanese troops releasing cholera bacteria into a stream with the intent of infecting civilians and enemy troops in towns downstream, but some of the Japanese soldiers who dispersed the causative agent contracted cholera, while the impact on the enemy and civilian population downstream was mild. Ishii discovered that the environment rapidly diluted and killed the bacteria. He needed a way for his disease agents to survive and find their human targets. He shifted his research to insect-vectored diseases: flea-borne bubonic plague and louse-borne typhus. He would enlist insects into war (Lockwood 2009).
Memorial. Most records were destroyed and the number and names of victims are mostly undocumented.
Bubonic plague became a major focus of the facility. Ishii’s teams worked to culture the most virulent strains of plague using fleas on mice and ground squirrels. Growing this bacterium without infecting the scientists or army personnel that would handle and distribute the disease meant inventing better hazmat suits. They had to seal off their infected animal colonies from outside animals and develop systems to safely distribute fleas in enemy territory.
Infected fleas carrying bubonic plague or lice carrying typhus were mixed with sand, and the mixture was placed in a porcelain bombshell. These bombs were dropped from planes and exploded about 300–500 feet above ground, with 80 percent of the insects surviving the explosion. To test the effectiveness of aerial dispersal, healthy prisoners were tied to crosses arranged in a large circular target area. An aerial bomb loaded with infected insects would be loaded aboard a plane and dropped from above the target, exploding in the air overhead. Within a short time, the infected insects found all of the bound prisoners, most of whom then died in two to 10 days.
In testing the virulence of bacterial strains on human victims, Ishii set a new standard for cruelty. Because the bodies of victims who died of bubonic plague rapidly decay, his workers conducted “autopsies” while the victim was still living in order to assess the organ damage before death. Anesthesia was not used. Young Japanese doctors found their first operations to be disturbing but soon became accustomed to the screaming as a victim was sliced open with a scalpel. These human victims were casually referred to as maruta—Japanese for “logs.” Films of these procedures were distributed in the military medical units. Over 100 science articles were published, often citing the use of “Manchurian monkeys,” but there were no monkeys native to Manchuria (Gold 1997, Harris 2002).
IN TESTING THE VIRULENCE OF BACTERIAL STRAINS ON HUMAN VICTIMS, ISHII SET A NEW STANDARD FOR CRUELTY.
Unit 731 Department Head Kawashima Kiyoshi confessed that “at least 3,000 people were used as subjects of live body experiments during the years from 1940 to 1945” (Harris 2002). These victims, originally just kidnapped from city streets, were eventually “special transfer” prisoners of war or captured enemy spies.
Wild animals were initially raised to serve as disease hosts.
Because of the difficulty of determining biological warfare deaths that may continue months or years after the attacks, exact numbers of casualties will never be known, but aerial bombardment of Chengde, Ningbo, and over a dozen other Chinese cities resulted in huge numbers of deaths from plague and typhus. Lockwood (2009) concludes that the “accepted figure” of deaths due to Unit 731’s Japanese biological warfare is “a total of 580,000 Chinese ... killed—slightly more than three-fourths by entomological weapons.”
As the war continued, Ishii also noticed that starvation took an even heavier toll in wartime China. In 1944, he began the culturing of agricultural pests to spread in enemy territory to destroy crops and create famine. However, Japan was now losing the war. Realizing the likely consequences of the discovery of Unit 731’s activities after Japan’s surrender on 14 August, Ishii ordered Chinese laborers to destroy Unit 731—and then executed them.
One might assume that Ishii Shiro and the ranking officials of Unit 731 would soon stand trial for war crimes at the International Military Tribunal in Tokyo in 1948, the eastern equivalent of the Nuremberg Trials in Europe. However, the members of Unit 731 who returned to Japan were never tried as war criminals. The first two American military investigations (the Sanders Report, 1 November 1945, and the Thompson Report, 31 May 1946; see Cunliffe 2006) disclosed the development of bacterial bombs and recommended an immunity-for-information deal. At the time, the United States was also pursuing biological warfare. Staff at Fort Detrick were eager to access scientific data that the U.S. military did not have. Two additional reports (the Fell Report, 20 June 1947, and the Hill and Victor Report, 12 December 1947; see Cunliffe 2006) interrogated Japanese researchers and fully described the human experiments conducted by Unit 731. The last report concluded that the immunity-for-information exchange was important because “such information could not be obtained in our own laboratories because of scruples attached to human experimentation” (Gold 1997, Harris 2002). Ishii Shiro would eventually die in bed at the age of 67.
Once infected, diseased animals were isolated in underground facilities. (Unit 731 developed early hazmat suits.)
“Bombs” that were designed to hold plague fleas or typhus lice.
However, the Russian Army had captured 12 members of Unit 731 and put them on trial from 25 to 31 December 1949 in Khabarovsk. This revealed to the world the Unit 731 operations: bubonic plague fleas dropped on civilians and inhumane human experimentation. The West dismissed the event as a Communist show trial. However, the Russians also negotiated clemency for information. Those 12 Japanese war criminals were eventually released and repatriated to Japan by 1956.
Many of the Japanese doctors who participated in the gruesome live autopsies at Unit 731 went on to rise to high positions in Japan: governor of Tokyo, the head of Japan’s biggest pharmaceutical company, the president of the Japan Medical Association, and other major offices. For nearly 40 years, the activities of Unit 731 went mostly unrecognized, but as many Unit 731 personnel reached old age, more details began to leak out. In 1997, Hal Gold summarized the operation of Unit 731 and published a hundred pages of translated testimonies of Japanese doctors, soldiers, and other workers in Unit 731 Testimony (Gold 1997).
Sheldon Harris, an emeritus professor of history at California State University–Northridge published Factories of Death, a scholarly summary of Unit 731, in 1994. Harris updated it with substantial additional research in the revised edition in 2002. The first half of his work is a heavily documented description of its operation. In 2003, reviewer Linda Goetz Holmes explained how “Those who had worked with Professor Harris in China, Japan, and the United States were gratified that he lived long enough to see his research vindicated by a court in Japan. Four days before he died, a Tokyo District Court made a decision which admitted, for the first time in that country’s judiciary, that Japan had used germ warfare in occupied China in the 1930s and 1940s.”
Some Unit 731 documents sent to the United States and labeled “top secret” were de-classified under Defense Secretary William Perry in 1993. They are now on view at the Unit 731 museum. The U.S. immunity-for-information deal and the Soviet Khabarovsk trial occupy additional rooms at the museum. Articles in the American Journal of Bioethics in 2006 and 2015 calling for a public U.S. recognition of the cover-up have gone ignored (Nie 2006, Devolder 2015), and American world history textbooks also remain silent about Unit 731 and the immunity-for-information deal.
Before I left the Harbin museum, I talked with their staff. “Do many Japanese visit this museum?” I asked.
“Yes,” was the reply. “Perhaps a dozen a week but more in some seasons. Some bring flowers. And some apologize.”
For all of its horrific images, the theme of this museum is not anti-Japanese. Yes, this museum stands as a repository of the documents and artifacts of this horrible time of warfare, but it ends with the same theme as the Nanjing War Museum—a caution to all of humanity. As one Japanese veteran stated without remorse: “When you are in war, you must do whatever you need to do to win.” The Unit 731 Museum in Harbin is here to help humanity avoid that path.
I am an entomologist. That is what brought me to the Unit 731 Museum. Robert Oppenheimer remarked upon the successful test of the atomic bomb that now “physicists have known sin.” Here at Pingfang, with the corpses and ashes of the victims of biowarfare experimentation buried under the ground on which I stood, is where entomology became evil.
John Richard Schrock received his doctorate from the University of Kansas in insect systematics and ecology, trained high school biology teachers at Emporia State University 1986-2016 and is biology professor emeritus. He has lectured at 28 universities in China and is English Editor of Entomotaxonomia, published by the Northwest Agricultural and Forestry University in Yangling, China.*
*HE HAS PUBLISHED COMMENTARIES ON THIS SUBJECT ON HIS PERSONAL WEBSITE (NOW CLOSED), WHICH HE SUBSEQUENTLY MADE AVAILABLE FOR REPUBLICATION. THIS WORK CONTAINS SOME OF THIS COMMENTARY MATERIAL, WHICH HAS BEEN ADAPTED FOR THIS AMERICAN ENTOMOLOGIST ARTICLE.
Suggested Resources
Barenblatt, D. 2004. A plague upon humanity: the secret genocide of Axis Japan’s germ warfare operation. Harper Collins, New York.
Pua, D., D. Dybbro, and A. Rogers. 2018. Unit 731: the forgotten Asian Auschwitz. Pacific Atrocities Education, San Francisco, California.
Wolfinger, K. (director). 2001. NOVA: Bioterror [DVD]. WGBH Educational Foundation, Boston, Massachusetts.
Yang, Y.J., and Y.J. Tam. 2018. Unit 731: laboratory of the devil, Auschwitz of the East. Fonthill Media, Oxford, United Kingdom.
