Regulations regarding biological weapons had already existed at the time with the Geneva Protocol of 1925. However, the Geneva Protocol only prohibited the use of biological weapons and did not regulate their development, production, or acquisition, leaving room for violations in the aforementioned areas. In fact, after reading a study on the Geneva Protocol’s prohibition on the use of biological weapons, Ishii was inspired to develop biological weapons (Selidik, 2020). He believed that if biological weapons are so dangerous that they have to be prohibited, then biological weapons are the best weapon. From there, Ishii began his research on biological warfare in a number of countries before returning to Japan in 1930.
The lack of regulation regarding biological weapons development then led Ishii to establish Unit 731 in a town near Harbin, China in 1931, shortly after Japan’s invasion of Manchuria. Initially, he conducted experiments on 1000 Chinese prisoners to see how their bodies would react if a certain amount of their blood was drawn every day. These experiments lasted until 1936, and the initial Unit 731 was terminated in 1937. However, Ishii built new research facilities for Unit 731 to conduct more cruel biological weapons experiments, such as research into biological bombs. By carrying out these sadistic experiments through Unit 731, Ishii Shiro had violated the principles of International Humanitarian Law. Ishii violated all five International Humanitarian Law principles: humanity, distinction, military necessity, proportionality, and limitation.
The principle of humanity refers to the obligation to protect human dignity and human rights by encouraging the protection of all individuals without discrimination. Unit 731 violated this principle by carrying out inhumane treatment, especially against prisoners of war and civilians who were used to be the objects of Unit 731’s experiments. Unit 731’s actions violated the principle of humanity, for example by carrying out experiments on injected prisoners with animal blood and horse urine to see the effects, heating prisoners to death to determine human resistance to temperature, and locked prisoners in a pressurized room until their eyes popped out to determine human resistance to pressure (Khawaja, 2023).
The principle of distinction is the principle of distinguishing or differentiating between civilians and combatants, as well as civilian objects and military targets. During a conflict or war, the parties must direct their operations solely against military targets. Ishii and Unit 731 violated this principle by inventing a germ bomb, a biological bomb made from fleas infected with plague and flies smeared with cholera. This germ bomb could not perform this distinction behavior and killed between 200,000 to 300,000 people when it was dropped on China (Selidik, 2020). The spread of the germ bomb was carried out by spreading insects by the Japanese military by spraying them from low-flying planes (Bethune, 2008). They targeted the entire city of Baoshan with victims throughout the city without exceptions, violating the principle of distinction between civilians and combatants.
Apart from the germ bomb, Unit 731 also conducted experiments involving civilians, such as criminals, political prisoners, and even pregnant women, children, and the elderly. The victims were unfairly arrested on false charges for cruel experimental purposes (Khawaja, 2023), indicating that Unit 731 violated the principle of distinction by involving civilians. Furthermore, Unit 731 conducted cruel experiments on pregnant women, children, and the elderly, all of whom were supposed to be protected during wartime.
The principle of military necessity or military objectives means focusing on military needs that are precisely suited to achieving the desired goal. This implies that the military should only use appropriate methods (including weapons) and select targets that pose the least risk to people’s lives and civilian objects. This principle was violated by Unit 731, which caused unnecessary extraordinary impacts. The germ bomb developed by Unit 731, for example, was not required to win the battle because Japan was militarily strong enough at the time. Furthermore, Unit 731’s experiments under the guise of military research were more akin to sadistic scientific experiments rather than legitimate military research.
The principle that was also violated was the principle of proportionality, which means taking into account not causing civilian casualties and excessive damage. In this case, Unit 731 had violated the proportionality principle by developing biological weapons with levels of cruelty and risk that were disproportionate to their purported research objectives. Biological weapons, such as the biological bombs developed by Unit 731 also resulted in high casualties and outbreaks of cholera and other diseases, which were clearly unnecessary to achieve the Japanese military’s goal of dominating the war.
The final principle of International Humanitarian Law that Ishii and Unit 731 violated in relation to biological weapons research was the limitation principle, which requires military operations to minimize unnecessary losses and casualties. In this case, the entire Unit 731 experiments were cruel and unnecessary, carried out in violation of ethical boundaries, and resulted in an infinite number of victims. The unit 731 biological bomb also caused an epidemic that was still spreading even ten years later (Bethune, 2008), indicating that there is no limit to minimizing the outbreak’s losses and victims.
Despite committing these various violations, Unit 731 researchers, particularly Ishii, were not prosecuted for violating International Humanitarian Law. In fact, despite clearly violating the Geneva Protocol’s prohibition on the use of biological weapons, Ishii was able to live his life in peace unpunished. This was due to the Allies (particularly the United States) granting Unit 731 amnesty in exchange for medical information and experiments (Selidik, 2020). This clearly demonstrates that there is injustice in international military courts and that stricter international law is required to regulate biological weapons, not only in terms of their use (which was regulated by the Geneva Protocol), but also in terms of their development.
Following the necessity of biological weapons regulation, in 1972, discussion on the issue of biological weapons regulation began through the Biological and Toxin Weapons Convention (BWC). This convention was negotiated in Geneva during the Conference of the Committee on Disarmament. The BWC supplements the Geneva Protocol of 1925, which only prohibited the use of biological weapons. The 184 that have signed the BWC has agreed not to develop, stockpile, obtain, or store microbes or other biological agents, toxins, weapons, or delivery devices related to biological weapons. The BWC was officially signed in 1975 and is reviewed on a regular basis (the most recent review took place from November 28 to December 16, 2022) to strengthen global norms against biological weapons (European Union External Action, 2022).
The BWC is a significant agreement that will help in preventing history from repeating itself as a result of weak regulations. The Geneva Protocol of 1925, which only regulated the use of biological weapons, encouraged Ishii (and possibly other researcher) to pursue biological weapons research. In the end, Ishii’s research led to Japan’s use of biological weapons, and ironically neither Japan nor Ishii were punished. This exemplifies the lax enforcement of biological regulations during World War II. With the BWC governing biological weapons as a whole, it is hoped that all parties, particularly countries, will refrain from conducting biological weapons research and development because the consequences are extremely dangerous and violate the five principles of International Humanitarian Law.