Japanese Unit 731 was a secret military unit of the Imperial Japanese Army
established in Manchuria (northeast China) during World War II. Its official
name was the “Kwantung Army Epidemic Prevention and Water Purification
Department.” In reality, however, it was a core institution engaged in
research for biological warfare (bacteriological warfare) and human
experimentation.

Overview of Core Crimes

The crimes of Unit 731 represent one of the darkest chapters in human history.
Its actions severely violated international law and the most fundamental
principles of human morality. Its main crimes can be divided into two
categories: crimes against humanity through human experimentation and the
practical application of bacteriological warfare.

1. Human Experimentation (Crimes Against Humanity)

The most horrifying crimes of Unit 731 were its systematic, large-scale, and
cruel experiments on live human beings. The victims, including Chinese
civilians, anti-Japanese resistance fighters, Soviets, and Koreans, were
contemptuously referred to as “Maruta“ (meaning “logs” or “lumber”) within
the unit. Experiments were often conducted on conscious victims without
anesthesia.

The main types of experiments included:

  1. Bacterial Infection Experiments:

    • Victims were deliberately infected with deadly bacteria such as plague, anthrax, cholera, and typhoid. Their disease progression, symptoms, and time until death were meticulously observed and recorded.
    • Vivisection was performed on infected individuals who were near death to obtain “fresh” organ data and study the spread of the bacteria within the human body.

  2. Vivisection:

    • Dissections were performed on victims who were fully conscious. The purpose was to observe the pathological changes in infected organs, test the efficacy of new drugs, or simply to fulfill “research” needs. This was a routine procedure for Unit 731.

  3. Frostbite Experiments:

    • In extreme cold, victims’ limbs were exposed or immersed in icy water to study different degrees of frostbite and potential treatments. The goal was to support Japanese military operations in cold regions. The thawing process was also brutal, often leading to muscle necrosis and exposed bone.

  4. Other Extreme and Weapon Testing:

    • Pressure Testing: Victims were placed in vacuum or high-pressure chambers to test human endurance, often until their internal organs ruptured.
    • Weapon Performance Testing: Victims were used to test the effects of grenades, bombs, flamethrowers, and germ-releasing bombs.
    • Other Experiments: These also included starvation and dehydration experiments, blood swapping experiments, and experiments with venereal diseases like syphilis.

2. Practical Application of Bacteriological Warfare

The research results of Unit 731 were directly applied on the battlefields in
China, where the unit launched multiple bacteriological warfare attacks against
Chinese civilians.

  • Methods: Using aircraft dispersal and manual spreading, the unit released

plague-infected fleas, rats, and bacteria-contaminated food and clothing over
numerous Chinese cities and counties, such as Ningbo in Zhejiang, Changde in
Hunan, and Jinhua.

  • Consequences: These actions caused large-scale outbreaks of plague,

cholera, and other virulent infectious diseases, resulting in the deaths of tens
of thousands of innocent civilians. This constituted organized, state-sponsored
bioterrorism.

3. Post-War Accountability and Historical Impact

  • Data Exchange and Immunity: After WWII, the commander of Unit 731, **Shiro

Ishii**, and others were not prosecuted at the Tokyo Trials. They secured
immunity from war crimes prosecution for themselves and their subordinates in
exchange for providing the United States with all of their human experimentation
and bacteriological warfare research data.

  • Cover-up of the Truth: Due to the onset of the Cold War, both the United

States and the Soviet Union were eager to acquire Japan’s biological warfare
data. This led to the deliberate cover-up of Unit 731’s crimes for a long time,
preventing a thorough legal reckoning and delivery of justice.

  • Ongoing Historical Issues: To this day, the Japanese government’s stance

on its history of aggression, particularly the crimes of Unit 731, remains
ambiguous. The lack of a thorough reflection and formal apology continues to be
a significant historical issue affecting Sino-Japanese relations.

Summary

The crimes of Japanese Unit 731 were systematic, state-sponsored atrocities
against humanity. They are not only a painful memory for the Chinese people but
also a shared lesson for all humankind. Understanding and remembering this
history is essential not only to honor the innocent victims but also to warn
future generations: Science must develop within the constraints of ethics and
morality. Any act that disregards life and tramples on human rights is a
betrayal of all human civilization.

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