


Ryoichi Naito
Surname | Naito |
Given Name | Ryoichi |
Country | Japan |
Category | Medicine |
Gender | Male |
Contributor: C. Peter Chen
ww2dbaseLieutenant Colonel Ryoichi Naito, a medical doctor specializing in microbiology, was a high ranking officer with the Epidemic Prevention and Water Purification Department (Unit 731) of the Japanese Army. In the 1930s and early 1940s, he operated in northeastern China, where he participated in programs involving pathogen weaponization and human experimentation. In mid-1942, he was made the second scientific head of OKA 9420 headquartered in Outram Park, Singapore (now the building hosting the Singapore Ministry of Health). Under his leadership, OKA 9420 spread to additional sites in Malaya (Permai Hospital in Tampoi, Johor, and a school in Kuala Pilah, Negeri Sembilan), employing about 150 physicians. His primary task was to prevent the spread of tropical diseases among Japanese military personnel; his team also ventured on side projects such as the creation of an anti-tetanus vaccine. Secretly, he also operated a major laboratory operation that cultivated pathogens such as bubonic plague, cholera, smallpox, malaria, typhus, dysentery, and anthrax. Under his direction, tens of thousands rats were trapped locally and brought in from abroad. These rats were injected with diseases and then fed to fleas; the fleas would then be used directly as weapons. The operation fled Singapore in Jun 1945 to Laos, far ahead of a possible British return. Naito was among the Unit 731 officers who were granted immunity by the Americans after the war, in exchange of the knowledge obtained through inhumane methods that the Americans could not conduct. He went on to have a successful career, cofounding the firm Japan Blood Bank (now the pharmaceutical firm Green Cross Corporation) in 1950; some of the fellow cofounders were also former members of Unit 731. He passed away in Jul 1982. In 1998, it was discovered that he had lied to the American occupation, saying that Unit 731 had never used humans in experiments.
ww2dbaseSources: "BiblioAsia", Singapore National Library Board
Last Major Revision: Jun 2019
Ryoichi Naito Timeline
1945年6月15日 | The Japanese OKA 9420 pathogen research facility at the Permai Hospital in Tampoi, Johor, Malaya was disbanded. The personnel was relocated to the main OKA 9420 laboratory in Outram Park, Singapore. |
1945年6月24日 | The Japanese OKA 9420 pathogen research operation was relocated from Singapore to Laos. All documents that remained behind were burned. |
請考慮透過 Patreon 支持本站。任何數量都會有莫大幫助!感謝您的支持。 請幫助宣傳: 訂閱 WW2DB,掌握最新動態: |
Visitor Submitted Comments
All visitor submitted comments are opinions of those making the submissions and do not reflect views of WW2DB.

- » Wreck of Teruzuki Found (2025年7月27日)
- » USS Orlean's Bow Found (2025年7月22日)
- » The Emperor of Japan Planned to Honor WW2-era Japanese POWs in Mongolia (2025年7月4日)
- » US State Lawmaker John Winter Caught Using Racial Slur "Jap" and Apologized (2025年6月11日)
- » US Government Plans to Purge WW2 Information (2025年3月17日)
- » 所有最新消息
- » 1,182 人物傳記
- » 337 事件
- » 45,119 時間軸條目
- » 1,248 軍艦
- » 350 飛機型號
- » 207 車輛型號
- » 376 兵器型號
- » 123 史料文件
- » 261 設施
- » 470 書評
- » 28,410 照片
- » 365 地圖
Captain Henry P. Jim Crowe, Guadalcanal, 13 Jan 1943
27 Jun 2019 12:31:11 AM
Isn’t he the 9420 band in Singapore manufacturing fleas carrying bubonic plague during ww2?