Yamaha.
Originally a musical instrument company, Yamaha produced large quantities of aircraft parts during the war, and some of its factories were seized.
Nikon.
Nikon specialized in optical equipment. During World War II, it supplied all of the Japanese military's binoculars, targeting sights, rangefinders, aerial cameras, and periscopes.
NEC.
During the war, together with Sumitomo Electric, NEC produced radar systems, wireless phones, vacuum tubes, and other electronic and semiconductor equipment for the Japanese army.
Nissan.
Nissan produced large numbers of military trucks and vehicles during World War II.
Isuzu.
Isuzu provided armored vehicles, tractors, and military trucks for the Japanese army during the war.
Nakajima Aircraft Company.
