DUTIES OF UNIT 731

Duties of Unit 731
Unit 731 claimed to the public that it was a "Water Supply and Epidemic Prevention" to the Imperial Japanese Army, but in reality, it was a site for the research and preparation of biological and chemical warfare. 
List of Experimentations​
bubonic plague
typhoid
tetanus
anthrax
cholera
glanders
dysentry
paratyphoid fever
gas gangrene
Mass Production of Pathogen
Pingfang was equipped with 4 boilers of one ton capacity each to produce the necessary sterilization to produce biological warfare pathogens in sterile growing environment for biological weapons. 
Breeding of Rats and Fleas to Spread Plague
Unit 731 raised rats and fleas in order to spread the pathogen that it produced. There were 96 cement pans to breed yellow rats and fleas. Pingfang had a target of keeping around 3 million rats annually. These rats were then infected with the plague and then the fleas were raised on the blood of the infected rats. 
Uji Bomb
The Imperial Japanese Army encased around 30,000 active and infected fleas into Uji bomb, ceramic bomb, and dropped them onto their targeted areas using planes. They used ceramic bomb because ceramic was easily shattered, which meant less of an explosion was required to have it opened. The plague-infected fleas were better protected with the less heat and pressure they were exposed to. They also tested on human subjects captured at Unit 731 to test how power these bombs and other biochemical weapons would be. 
Other "Water Supply and Epidemic Prevention" Units of the Japanese Army
   Southern Army: Unit 9420 in Singapore
   Southern Branch Army: Unit 8604 in Guangdong
   Central Branch Army: Unit 1644 in Nanjing
   Northern Branch Army: Unit 1855 in Beijing
   Kwantung Army: Unit 731 in Harbin, Unit 100 in Changchun
Related Book

Unit 731- The Forgotten Asian Auschwitz

The Japanese invasion of China during the Second Sino-Japanese war has left a strong legacy of hate and disgust among many Chinese today. Much of the atrocities committed by the Japanese are now known to most historians. By far, the most despicable and forgotten act against humanity committed by the Imperial Japanese government was its covert biochemical weapons program. Euphemistically labelled as the "Epidemic Prevention and Water Purification Department" of the Imperial Japanese Army, the Japanese conducted a wide range of cruel and inhumane experiments on prisoners who were often innocent.