Sumida Model J 4X2 military passenger vehicle was produced in 1933, and the production of the 4X4 Sumida Model JC began in 1937 to further enhance the travelling performance on uneven terrains.

The new model incorporated experimental mechanisms such as differential lock of the rear axle that deactivated the differential system temporarily when, for example, one of the rear wheels was caught in a ditch.

The same year, a prototype of the 4X2 diesel-powered Sumida Model JD was also built. The model—equipped with a 4.2L DC 6 engine—was developed to participate in a diesel engine development competition organized by the Army’s automobile school and scored high in the test drives in Hakone Pass and on the road around Mount Fuji.