Imperial Japanese Army

Imperial Japanese Army

-Foundation:During the Meiji Restoration, the military forces loyal to the Emperor were samurai drawn primarily from the loyalist feudal domains of Satsuma and Chōshū...

Formed in 1942 to support the Japanese Southern Army, Unit 9420 or Oka Unit consisted of two units; the Umeoka Unit, which specialised in the plague

Bubonic plague

Plague is a deadly infectious disease that is caused by the enterobacteria Yersinia pestis, named after the French-Swiss bacteriologist Alexandre Yersin. Primarily carried by rodents and spread to humans via fleas, the disease is notorious throughout history, due to the unrivaled scale of death...

, and the Kono Unit, which specialised in malaria

Malaria

Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

.

Commanded by Major General Kitagawa Masataka, the unit was headquartered in the Permai Hospital in Tampoi, Johor

Johor

Johor is a Malaysian state, located in the southern portion of Peninsular Malaysia. It is one of the most developed states in Malaysia. The state capital city and royal city of Johor is Johor Bahru, formerly known as Tanjung Puteri...

, near the southern tip of the Malay Peninsula

Malay Peninsula

The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...

, 13 km northeast of Johor Bahru

Johor Bahru

Johor Bahru is the capital city of Johor in southern Malaysia. Johor Bahru is the southernmost city of the Eurasian mainland...

 and Singapore

Singapore

Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...

, with some evidence that it also had sub-units operating in Thailand and working on unknown diseases. Coupled to its work on the plague, the unit was also responsible for rat catching.