It was conceived in 1934 by the Japanese Imperial Army as a small rough terrain vehicle to do reconnaissance, deliver messages to the field, and transport personnel. The military asked Toyota, Hatsudoki Seizo, Rikuo Internal Combustion Engine, and Okamoto to collaborate with Kurogane to design and manufacture the new vehicle. Toyota MVD was building the Toyota G1, and Okamoto Bicycle and Automobile Manufacturing, was manufacturing bicycles for the Imperial Japanese Navy, and was absorbed into Toyota in 1972. The prototype was the result, using a Japanese-built internal combustion engine. Mass-production began in 1936. At the time, military operations in Mainland China and Southeast Asia, a mass-produced military vehicle equipped with Japan's first four-wheel drive mechanism, increased mobility in the area'a rough terrain. In 1934, Mitsubishi Heavy Industries had internally developed a prototype, four-door, four-wheel-drive sedan for personnel transport, called the Mitsubishi PX33, which was powered by a 6.7-litre four-cylinder diesel engine. Four prototypes were built before the project was cancelled.