8. As part of a range of environmental conditional testing, prisoners of war had limbs deliberately exposed to frostbite and were sealed in high-pressure chambers to observe the limitations of the human body
Among the countless horrific experiments performed on Allied prisoners, Dr. Yoshimura Hisato of Unit 731 became fascinated in exploring the effects of frostbite upon the human body. Freezing certain body parts, these appendages “when struck with a short stick, emitted a sound resembling that which a board gives when it is struck”. Thereafter, ice was chipped away to determine the scale of the tissue damage and lasting physiological consequences of severe freezing.
In one particularly gruesome recollection, a former guard recounted how, in the course of raping female Chinese prisoners, his group had encountered a woman who “had been used in a frostbite experiment. She had several fingers missing and her bones were black, with gangrene set in. He was about to rape her anyway, then he saw that her sex organ was festering, with pus oozing to the surface. He gave up the idea”. Not isolated to only the extremes of cold, Japanese researchers sought to understand the effects of a wide range of environmental conditions including pressure – placing individuals in high-pressure chambers until their eyeballs popped out – and radiation – caused by exposing prisoners to lethal x-rays.
7. In violation of international law, Allied airmen were refused the title of “prisoner of war”, instead of being treated as criminals and frequently executed after show trials
According to the Hague Convention of 1907, of which Japan was a signatory, any military personnel captured in war could not be punished for being lawful enemy combatants. On August 13, 1942, Imperial Japan enacted the Enemy Airmen’s Act, passed in response to the Doolittle Raid, stipulating that any Allied pilots who bombed non-military targets in the Pacific Theater would be treated as criminal and not a prisoner of war if caught. Eight airmen from the Doolittle Raid were brought before a Shanghai court, where they were refused the opportunity to mount any legal defense to their charges and three were sentenced to death by firing squad.
This act marked the beginnings of the recurrent prosecution and execution of Allied POWs under the illusion of criminal justice. In total, an estimated 132 Allied airmen shot down during the 1944-1945 bombing campaign were convicted and executed by Japanese show trials. A further 94 died whilst in custody, in addition to an unknown figure as a result of tolerated public lynchings. Most egregiously, 15 captured Allied airmen were hurriedly beheaded on August 15, 1945, at Fukuoka, shortly after the Japanese Government announced its intention to surrender to the Allies.
6. Facing Allied liberation, almost 150 POWs held at Puerto Princesa in the Philippines were massacred by the Japanese rather than be allowed to be free
In response to advancing Allied forces in the Philippines, on December 14, 1944, soldiers of the Japanese Fourteenth Area Army, under the command of General Tomoyuki Yamashita, initiated the aforementioned liquidation order of the War Ministry. In an attempt to prevent the approximately 150 POWs held at Puerto Princesa, located in the Philippine province of Palawan, from being rescued by their comrades, these prisoners were herded by the Japanese into shelter trenches under the pretext of an incoming air raid. Once assembled, the POWs were doused in gasoline and set on fire; those who attempted to escape the flames were shot by machine gun.
In total, just 11 of the 150 prisoners survived, scaling a cliff along the side of the trench. The testimony of one of these survivors, Private First Class Eugene Nielsen, sparked outrage and a mass operation by the Allies to retrieve as many of their captured soldiers before they could be similarly executed by the Japanese. On January 30, the U.S. launched a raid on Cabanatuan, on February 3 at Santo Tomas Internment Camp, on February 4 at Bilibid Prison, and on February 23 at Los Baños. Although 16 Japanese soldiers were sentenced to death in 1948 for their role in the Palawan Massacre, they were released as part of an amnesty before execution.
5. Human experimentation on Allied prisoners of war extended to the fatal injection of animal blood as part of the search for medically viable substitutes for front-line transfusions
As noted, much of the human experimentation conducted by the Empire of Japan on Allied prisoners of war was done in the name of preservation. Seeking to find more effective methods to protect and repair their own soldiers the Japanese were prepared to sacrifice those they captured in the course of the Second World War, individuals that were culturally viewed as innately inferior to the superior “Yamato” race. Consequently, much of the research that was conducted by Japanese scientists, notably those employed by Unit 731, focused on the conditional limits of survival, medicinal practices, and physiological endurance.
One such noteworthy medical experiment included the injection of animal blood into humans as a test case for blood transfusions. Horse blood was administered to Allied POWs to explore the possibility of using non-human blood as a substitute for increasingly scarce supplies of human blood on the front lines. Unsurprisingly, the procedure was a failure, resulting in the deaths of the prisoners in the trial. Similarly, prisoners were forcibly injected with concoctions including seawater; these tests, likewise, proved fatal.
4. Towards the end of the war, with supplies running low, the Japanese resorted to the murder and cannibalism of Allied POWs
Committed in response to Allied attacks on Japanese supply lines, resulting in widespread starvation among Japanese soldiers, according to historian Yuki Tanaka “cannibalism was often a systematic activity conducted by whole squads and under the command of officers”. Many of these acts were the product of murder to acquire the meat, with Indian POW Changdi Ram testifying that on November 12, 1944, “the Kempeitai beheaded [an Allied] pilot. I saw this from behind a tree and watched some of the Japanese cut flesh from his arms, legs, hips, buttocks and carry it off to their quarters … They cut it [into] small pieces and fried it”.
Similar instances were systematically corroborated by other Allied prisoners, with Hatam Ali recounting that in New Guinea “the Japanese started selecting prisoners and every day one prisoner was taken out and killed and eaten by the soldiers. I personally saw this happen and about 100 prisoners were eaten at this place by the Japanese. The remainder of us were taken to another spot 50 miles [80 km] away where 10 prisoners died of sickness. At this place, the Japanese again started selecting prisoners to eat. Those selected were taken to a hut where their flesh was cut from their bodies while they were alive and they were thrown into a ditch where they later died.”
3. With diseases the leading cause of soldier fatality, Japanese researchers began testing vaccines on deliberately infected prisoners to determine their effects on humans
In the course of the Sino-Japanese War (1937-1945), the Japanese discovered a horrid truth about modern warfare: that the overwhelming majority, in fact as high as 89 percent, of battlefield fatalities were caused not by the fighting but from diseases. In an attempt to better understand these illnesses, in addition to synthesizing vaccinations and cures, researchers at Unit 731 deliberately infected POWs. Forming one of the eight core divisions of Unit 731, this division, numbering approximately 300 researchers, focused on bacteriological diseases, notably cholera, anthrax, typhoid, tuberculosis, and the plague.
Some of the findings of researchers from Unit 731 were published contemporaneously in peer-reviewed journals, disguising that the research had been conducted on non-human primates. Subjects, for example, Chinese prisoners, were referred to as “Manchurian monkeys” or “long-tailed monkeys”, reflecting the sub-human nature in which POWs were viewed by the Japanese Empire. Their corpses were subsequently incinerated to eliminate evidence of wrongdoing by the Japanese military. The consequences of these methods can be seen in Indonesia on August 6, 1944, where an estimated 900 men were injected with an experimental vaccine. This vaccine, designed to combat tetanus, instead induced a fatal reaction to those administered; in total, it is believed nearly 1,000 people were killed by this failed test.
2. The Japanese repeatedly forced Allied prisoners of war to embark on prolonged marches with little to no provisions, resulting in the deaths of thousands
In the aftermath of the Battle of Bataan and the surrender of Allied forces in the Philippines, captured prisoners of war needed to be relocated to be housed and exploited for labor. Beginning on April 2, 1942, between 60,000 to 80,000 POWs were marched from Mariveles to San Fernando, loaded onto trains to Campas Train Station, and marched from there to Camp O’Donnell – a total of approximately 70 miles by foot. During this forced march, in which POWs were provided little to no food or water, and those that requested provisions were shot by the Japanese, an estimated 18,000 Filipino prisoners and 650 Americans died.
Such marches were not uncommon for Allied prisoners during the Second World War, with the Sandakan Death March similarly occurring in 1945. Facing Allied invasion, the Japanese sought to move POWs into the mountains to prevent easy liberation. From January to March, a total of 470 POWs were marched into the mountains; with limited rations, and suffering from serious illnesses, just 6 were still alive by June 26. The second round of prisoners was marched from May, whereupon just 183 out of 536 POWs survived the journey. A final round, starting in June, comprised of 75 prisoners, was marched into the mountains, with not a single one lasting more than 50 kilometers of the journey.
1. Allied POWs were used as human subjects of weapons tests, both for conventional armaments and for biological weaponry
As with all weaponry, tests must be conducted to determine their efficacy and during World War II the Japanese military opted for using Allied prisoners as human guinea pigs for these new technologies. POWs were tied to stakes whilst jars of cyanide were thrown at them, recorded in November 1944 in the Kai Islands, set alight with flamethrowers, targeted with tank cannons, and to test the range of grenade explosions. Most horrifically, prisoners were consciously exposed to diseases, such as typhoid and plague, and monitored to determine the effects of prolonged exposure and observe the deterioration of the afflicted.
The use of biological weapons by the Japanese was confirmed, with Chinese and South Asian targets bombarded with plague-infected fleas dispersed over populations by planes. An estimated 580,000 people were killed by the Imperial Japanese Army’s deliberate spread of plagues during the Second World War. In fact, during the concluding months of the war, Japan planned to unleashed biological weapons upon the mainland United States. Operation Cherry Blossoms at Night, using diseases concocted by Unit 731 using prisoner research, was intended to release plagues against the civilian inhabitants of San Diego, California, starting on September 22, 1945.