The Shoda-Hikoki Company, a minor contributor to the Japanese World War II effort, began developing a scaled-down, air-cooled version of the liquid-cooled Daimler-Benz DB 601 aircraft engine in 1940. It was the Shoda Company’s only foray into aircraft engines. The Shoda-Ken was an experimental engine project, not intended for production, and never fitted to an airframe. The engine features two-stage supercharging and a viscous coupling supercharger drive.

The Shoda-Ken includes a unique technical development where the cylinder head cooling fins were “hot-fused” into the cylinder head during the forging process, a technique investigated by the National Advisory Committee for Aeronautics in the late 1930s. The “hot-fused” fin process involves preassembly of sheet aluminum fins, placing them in a jig in the desired pitch and then forcing them into the partially molten cylinder head blank during the forging process. This type of head fin was produced by Shoda as a subcontractor to Nakajima for Homare cylinder heads during World War II.

Extensive testing engine began at the Yokosuka Naval Air Arsenal in 1943. Only two engines, plus spare parts sufficient for a third, were built with this one being the sole survivor.