While the horrors of concentration and prisoner of war camps during World War II are well-documented, many remain unaware of a sinister human experimentation complex that operated in China for nearly a decade.

Unit 731, also known as the Manchu Detachment 731, was a clandestine research facility run by the Imperial Japanese Army. This facility was the epicentre of large-scale biological and chemical warfare research, often involving deadly human experimentation.

Buildings seven and eight were the nerve centres of this chilling ‘research’, shrouded in secrecy and heavily guarded. Building seven housed male victims, while building eight was designated for females and children.

These structures were designed to accommodate a staggering 400 inmates, although it’s believed that around 200 individuals could be present at any given time. In a grim testament to efficiency, each cell was meticulously designed with a low-set window for easy blood sample collection. The walls, up to 40cm thick, enclosed each victim along with a flushable toilet.

The cells were maintained in pristine condition, ensuring the ‘quality’ of the horrifying work conducted within. The exact number of victims who perished at the hands of Unit 731’s researchers remains unknown, as it’s believed that once the count reached 1,500, they restarted from 101.

In a chilling display of inhumanity, prisoners were intentionally infected with various diseases, masquerading as vaccinations, to observe their reactions. Victims were often subjected to a cocktail of lethal infections as part of the grotesque experiments conducted by those overseeing this hellish facility.

These included plague, cholera, anthrax, and typhoid bacteria, all administered with the objective of studying the prisoners’ responses to these diseases. Some were infected with syphilis and gonorrhoea, while the researchers coldly observed their reactions.

It is speculated that the ultimate goal was to utilise the findings to advance the development of biological weapons for warfare. However, if a prisoner survived any form of inoculation, they would be subjected to repeated experiments without any treatment unless it aided their testing methods. Consequently, no prisoner ever escaped this facility alive.

The atrocities committed within the facility didn’t end there. One of the horrific experimental methods employed involved vivisection. Prisoners were dissected alive, typically without any anaesthesia, allowing the onsite doctors to study the effects of the deliberately induced diseases on their internal organs.

In a further horrifying exploration of the diseases’ effects, female prisoners were subjected to rape and forced pregnancy. This was a strategy to investigate how disease transmission impacted women during pregnancy and their unborn children.

In other brutal instances, these individuals were treated as mere playthings, with guards using them as live targets for weapons testing. Prisoners were made to face grenades, flamethrowers and other weapons, and once severely injured, they were dissected so their wounds could be studied.

Frostbite testing was another cruel experiment inflicted on the victims, exposing people to extreme cold to examine the effects of frostbite and test potential treatments. Consequently, entire limbs would be frozen and later thawed to inspect the unique nerve damage caused.

Those specifically selected for participation in these experiments were typically accused of any crime ranging from opium smoking to communism, as well as individuals suffering from mental illnesses or homelessness. Those unfortunate enough to end up at Unit 731 were only ever brought into the building via a secret tunnel, leaving them with no knowledge of their exact location.

Nakagawa Yonezo, a professor at Osaka University, recounted viewing footage of the human experiments conducted at Unit 731 during his studies in the war period. He later testified that he believes many of these experiments were not performed for medical purposes but out of sheer curiosity and ‘playfulness’.