The institute was the brainchild of Dr Shiro Ishii of Kyoto University, and he was given unlimited resources to build his research laboratories, such as Unit 731. The design of the building was of the highest specifications, with the very best of materials and the latest equipment. Harbin was chosen for its remoteness from the rest of China, and the local workers who were erecting the buildings were told that it was to be a timber mill. The best local craftsmen were used, and the highest quality materials brought in, regardless of expense.
For decades, little emerged about the work, though it was widely believed that thousands of people died as a result of these grotesque medical experiments. Not until 2002 was a formal academic meeting held that examined the surviving documents in detail. Their revelations were deeply disturbing: over half a million people died as a result of Japan’s medical experimentation in camps like Unit 731. The clue to the importance of this research, exactly as in the case of the Treaty of Versailles, lay in international legislation enacted specifically to prevent it. Historian Daniel Barenblatt has put his finger on the dawn of this practice in Japan, when Ishii read a report on the Geneva Convention, published in 1925, which stated:
The use in war of asphyxiating, poisonous, or other gases … has been justly condemned by the general opinion of the civilized world … and [we] agree to extend this prohibition to the use of bacteriological methods of warfare.
Ishii had long tried to convince the Japanese authorities of the value of bacteriological weapons in war, and they had never taken him seriously. Here was the evidence he needed — if bacteriological warfare was regarded as such a threat as to warrant an entire section of the Geneva Convention, then that proved how valuable it could be to Japan. By prohibiting germ warfare, the Convention had clearly documented its potential importance.
To Ishii, the enemy were different — he saw them, as increasing numbers of Japanese were to do, as inferior beings, subservient to Japan, and there only to be used at the will of the conquering Japanese Empire. Unit 731 was the first and main establishment, and others soon followed, including Unit 100 (Changchun), Unit 200 (Manchuria), Unit 516 (Qiqihar), Unit 543 (Hailar), Unit 773 (Songo unit), Unit Ei 1644 (Nanjing), Unit 1855 (Beijing), Unit 8604 (Guangzhou) and Unit 9420 (Singapore).
The experimental subjects were treated worse than livestock. They were brought in from areas occupied by the Japanese in China and Korea, and were held in enclosures. Some were criminals and bandits, others were military prisoners, more still were women — some pregnant — and children, together with the old. One of the stories circulated to explain the new institutes was that one was a lumber mill. It gave rise to the Japanese nickname for the inmates of ‘logs’. As military historian Sheldon H. Harris has said, ‘they were regarded as logs — you could cut them or burn them with impunity’. In consequence, these hapless prisoners were frequently subjected to vivisection, having limbs or organs removed to study the effects. Men had their extremities frozen until they became gangrenous, so the course of the agonizing fatal infection could be studied. Women were cut open so that their foetuses could be studied; others had limbs cut off so that death through blood loss could be observed. People had air let into veins, to study how they died; some were hung upside down to see how long they survived, others were treated in high-pressure chambers, were spun until dead on giant centrifuges or injected with urine and seawater. Prisoners were also tied to posts and subjected to weapons testing and used for target practice. Others were blown apart by grenades, burned alive with flame throwers and doused with caustic chemicals. The records were written up in meticulous detail, so that Japanese troops — when injured by blast, chemicals or intense cold — could be treated with a better insight into how their wounds would progress. Other victims were injected with disease agents including syphilis or infected with disease vectors like fleas, to see how the diseases were transmitted. Cholera, plague and anthrax were deliberately spread among civilian populations to facilitate ethnic cleansing and to investigate the potential of these diseases as biological weapons.
Secret biowarfare agents resulted. Planes flew low over Chinese cities to spray infected fleas in huge amounts. There were epidemics of bubonic plague spread by this means. Infected food was dropped for starving villagers, epidemics of dysentery, typhoid and even cholera were caused deliberately. Doctors and technicians in protective suits would move among the populations to observe how they died. The International Symposium on the Crimes of Bacteriological Warfare concluded in 2002 that the number of people killed by the Imperial Japanese Army in their medical experiments was around 580,000.
As the war entered its closing phase, Soviet troops invaded Manchukuo in August 1945 and the medical experimentation staff returned to Japan. All were issued with cyanide pills to take in an emergency, and Ishii instructed everyone that they should never speak of what had happened. A few staff remained on site with instructions to blow up the buildings as the enemy troops approached. In the event, the buildings had been constructed too strongly to be so easily demolished, and most were unaffected by the explosives. Today some are museums.
When the Empire of Japan surrendered to the Allies in 1945, the Supreme Commander of the Allied Forces, General Douglas MacArthur, was given the responsibility or restoring peace to Japan. The work at the secret camps had all been well documented, and the research scientists and doctors were all known to the Allies as being among the most sadistic and inhuman individuals of the entire war. They were all immediately categorized as culpable war criminals. Those who had been apprehended by the Soviets were prosecuted at the Khabarovsk War Crime Trials. Twelve of the top researchers and commanders were prosecuted for their crimes. One was the Commander-in-Chief of the Kwantung Army that occupied Manchuria. He was General Otozo Yamada, in charge of the biological warfare research. He was sentenced to 25 years in a Siberian work camp but was released to return to Japan in 1956. Meanwhile, the Soviets went on to establish a biological research institute in Sverdlovsk that was founded on the findings from Unit 731.
The researchers who were captured by the Western Allies, or surrendered to American forces, were treated very differently. Ishii had lengthy discussions with the Americans and was treated well during his confinement. In May 1947, General MacArthur entered a plea bargain with the Japanese. He informed Washington that, if the perpetrators were guaranteed immunity from prosecution, the United States could benefit from all their findings. The results would not be made available to any other nation. The deal was agreed and, when the Tokyo War Crimes Tribunal convened to try Japanese war criminals, only one case of human experimentation was brought before the courts. This was the alleged use of poisonous serum against Chinese civilians, and the case was dismissed due to insufficient evidence. Large numbers of those Japanese workers who had carried out the inhuman research were offered freedom in exchange for their findings, and went on to hold positions of importance in academia, politics and business. Many of them practised medicine after the war. One became the head of the leading Japanese pharmaceutical company; another became president of a prestigious American medical school.