“[Ishii’s] talents for biomedical research as proved through his published scientific papers, and his drive to make Japan the foremost nation in biological warfare, was the same vision shared by Koizumi"- Daniel Barenblatt, author of A Plague Upon Humanity
Koizumi was the main supporter for Unit 731 and acquired funding for its experimentation. After developing Japan's first chemical weapons in 1918, he was regarded as the "Father of Japanese Chemical Warfare". He helped Shiro Ishii develop Unit 731 and Japan's biological warfare program.
Encounter with the United States
After the conclusion of World War II, he committed seppuku rather than turn himself in to American forces.