Japanese Unit 731 will be remembered as a part of Japan’s history for vicious crimes committed which included vivisection, limb amputation, frostbite testing, and syphilis, and forced pregnancy and all of this was performed on people, just like a lab rat the experiment was conducted on humans this time. The estimated killing by experiments in Japanese Unit 731 and related programs range up to half a million people.

Unit 731
Unit 731, Wikimedia Commons

What was Japanese Unit 731?

Unit 731, also referred to as Detachment 731, the 731 Regiment, Japanese Unit 731, Manshu Detachment 731, The Kamo Detachment, Ishii Unit or Ishii company was a covert biological and chemical warfare research and development unit of the Imperial Japanese Army that undertook lethal human experimentation during the Second Sino-Japanese War of World War II.

A special project code-named Maruta used human beings for experiments. Locals were used as test subjects and referred to as “logs” and used in contexts such as “How many logs fell?”. The test subjects were selected to give a wide-cross selection of the population and included common criminals, captured bandits, anti-Japanese partisans, political prisoners, the homeless and mentally handicapped and also people rounded by Kempeitai military police for suspicious reasons. They included infants, the elderly and pregnant women. Unit 731 had branches in Linkou. (Branch 162)

The members of unit 731 were approximately 300 researchers, which included doctors and bacteriologists.

Prisoners were injected with diseases, disguised as vaccinations. To study the effect of venereal diseases, male and female prisoners were deliberately infected with syphilis and gonorrhea. The prisoners were repeatedly raped by the guards.

Most disturbing “experiments” conducted by Japanese Unit 731

From 1942 to 1945, General Shiro Ishii conducted shockingly cruel experiments perpetrated on human beings the world has ever known. All experiments were in the name of Medical research meant to defeat Japan’s wartime enemies.

General Shiro Ishii, the commander of Unit 731.
General Shiro Ishii, the Commander of Unit 731. Wikimedia Commons.

The worst a human can face in Unit 731 experiments

At, first the patients were volunteers from the ranks of the army but as the numbers reached high, thousand of men, women, children, and infants interned at a prisoner of war camps to vivisection, without anesthesia which usually resulted in the death of the victim.

Vivisections were performed on the prisoners after infecting them with various diseases. The patients were kept alive during the time their organs were removed. Patients were kept alive as it was thought that the result would change.

 A Unit 731 doctor operates on a patient that is part of a bacteriological experiment. Date unspecified.
A Unit 731 doctor operates on a patient that is part of a bacteriological experiment. Date unspecified. Xinhua via Getty Images

Prisoners had limbs amputated in order to study loss, the limbs would sometimes be re-attached to the opposite side of the body. Not just limbs other organs such as the brain, lungs, and livers were removed from some prisoners. Japanese Army surgeon Ken Yuasa suggests that the practice of vivisection on human subjects was widespread and at least 1,000 Japanese personals were involved in the practice in mainland China.


Unit 731 Frostbite Testing

A physiologist assigned to unit 731 conducted experiments by taking captives outside, dipping various appendages into the water and allowing them to freeze, until the arm or the leg had frozen solid and a coat of ice had formed over the skin. A Japanese officer said in his testimony that “was determined after the frozen arms when struck with a short stick, emitted a sound resembling that which a board gives when it is struck.”

The limbs were brought close to the fire and several methods were used to determine the effect it had on frostbite, as the effect was tested by bludgeoning the victim to determine if any areas were still frozen.

Syphilis happened in Unit 731 experiments

Unit 731 members were orchestrated forced sex act between infected and non-infects prisoners to transmit the disease, as the infection of venereal disease by injunction was abandoned and the researchers started forcing the prisoners into sexual acts with each other.

Anyone of the male and female was effected and the sexual act was done in front of four or five unit members, who will be dressed from to bottom with only eyes and mouth visible.


It was made clear that anyone who did not co-operate or resist would be shot. After the victims were infected, vivisection took place so the effect of disease on body organs can be studied. Genitals of infected female prisoners with Syphilis were called “Jam filled buns” by guards.

Even some children grew up inside the walls of Unit 731, infected with syphilis. The children were tasted the same way as their parents were, with specific emphasis on determining how longer infection periods affected the effectiveness of treatments.

Weapon Test in Unit 731 Experiments

It is common to test weapons before going to the war, but it is uncommon to test weapons on living humans. In unit 731, human targets were used to test grenades positioned at various distances and in various positions. Flamethrowers were tested on humans. Humans were tied for the tests of pathogen releasing bombs, chemical weapons, explosive bombs as well as for bayonets and knives.

 A Japanese soldier uses a Chinese man’s body for bayonet practice near Tianjin, China.
A Japanese soldier uses a Chinese man’s body for bayonet practice near Tianjin, China. September 1937. Wikimedia Commons

Rape and forced pregnancy

Female prisoners were forced to become pregnant for use in experiments. The reason stated for the torture was to study the possibility of vertical transmission of diseases, particularly syphilis. Which resulted in a large number of newborns in captivity. While male prisoners were often used in single studies so that the results of the experimentation on them would not be clouded by other variables.

The situation for women’s living in unit 731 was not less than hell as a testimony of a training guard told about the horrific experience he had to see “one of the former researchers I located told me that one day he had a human experiment scheduled, but there was still time to kill. So he and another unit member took the keys to the cells and opened one that housed a Chinese woman. One of the unit members raped her; the other member took the keys and opened another cell. There was a Chinese woman in there 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, left and locked the door, then later went on to his experimental work.”

Unit 731 — Biological Warfare

Unit 731 and its affiliated units were involved in research, development and experimental deployment of epidemic creating biowarfare weapons in assaults against the Chinese populace through world war II.

Plague-infected fleas, made in laboratories of Unit 731 and Unit 1644, were spread by low-flying airplanes upon Chinese cities in 1940 and 1941. Epidemics broke out shortly after and were the most effective pathogens.

Unit 731’s Harbin facility.
Unit 731’s Harbin facility. Wikimedia commons

11 Chinese cities were attacked with biological agents and at least 12 large scale field trials of biological weapons were performed. An attack on Changda in 1941 led to approximately 10,000 biological casualties and 1700 deaths among ill-prepared Japanese troops.

In August 1945 Hiroshima and Nagasaki had both been bombed.

Unit 731 was divided into eight divisions

  • Division 1: For research on bubonic plague, cholera, anthrax, typhoid, and tuberculosis and for this purpose, a prison was constructed with a capacity of three to four hundred people.
  • Division 2: Research for Biological weapons used in the filed, in particular, the devices which spread germs and parasites.
  • Division 3: Production of shells.
  • Division 4:Bacteria mass production and storage.
  • Division 5: Personals training.
  • Division6,7,8: Equipment, Medical, and Administrative units.

One member of Unit 731 later recalled that very sick and unresisting prisoners would be laid out on the slab so a line could be inserted into their carotid artery. When most of the blood had been siphoned off and his heart was too weak to pump anymore, an officer in leather boots climbed onto the table and jumped on the victim’s chest with enough force to crush the ribcage.

Surrender by Shiro Ishii

The commander of Unit 731 surrendered at the end of the war. Shiro Ishii wanted to use biological weapons in the Pacific War since May 1944, but his attempts were repeatedly snubbed. When the Red Army came in August 1945, the units ordered to destroy the evidence, such as 300 remeaning prisoners were either gassed or fed poison and the remaining 600 Chinese and Manchurian Laborers were shot.

Shiro Ishii was so scared that he told every member of his group to disappear and take the secret to the grave. In 1946 US General Douglas MacArthur granted all the Japanese scientist’s immunity from war crimes prosecution in exchange for the germ warfare data gathered from experiments in Harbin and none of the Japanese scientists in Unit 731 was ever punished.

Unit 731 and the SS Ourang Medan

There was another story attached to Unit 731 about a mysterious cursed death ship named SS Ourang Medan. An SOS signal was received from the Ourang Medan on a stormy night, one of the other ship on catching the signal decided to respond to the help call. Upon boarding the aimlessly floating Ourang Medan, the scene that the helping crew saw was just unexplanatory.

Every single living thing on the Ourang Medan was dead, with their hands and legs froze with a horrifying reflection on their faces as they might have seen something demonic moments before their death, not even the only animal, a dog was alive.

Upon searching the ship for a while they also found two of the operators trying to shield the door from something but their bodies frozen in the same position and also the operator lying on the floor who probably have sent the signal.

What happened on SS Ourang Medan is still unknown, but many believed that the ship was carrying chemicals or substances from the Unit 731 experiments and that lead to the death of every single person on the ship, that’s why FBI was also interested in the mysterious death ship. Read the full story about SS Ourang Medan.

Now since you have read about the Japanese Unit 731 experiments, you might like reading about The Secret Mind control program MK Ultra. You might also like reading about how UFO Conspiracy Theorist Max Spiers was killed.

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