The Atsuta 31 was a licensed version of the Daimler-Benz DB 601A liquid-cooled, inverted V-12 engine. The Atsuta reduced an aircraft’s frontal area, increasing aerodynamic efficiency. Aichi manufactured 873 Atsuta series engines during World War II.
The Atsuta was the only liquid-cooled engine used operationally by the Japanese naval air force. The Ha 60 Model 31 powered the Aichi M6A1 Seiran, a submarine-borne floatplane bomber, and early versions of the Yokosuka D4Y2 series Suisei carrier-based dive bomber and reconnaissance aircraft.