In Japan, the Jupiter was licence-built from 1924 by Nakajima, forming the basis of their own subsequent radial aero-engine design, the Nakajima Ha-1 Kotobuki.[6] It was produced in Poland as the PZL Bristol Jupiter, in Italy as the Alfa Romeo 126-RC35,[7] and in Czechoslovakia by Walter Engines. The most produced version was in the Soviet Union, where their Shvetsov M-22 version powered the initial Type 4 version of the Polikarpov I-16 (55 units produced). Type 4 Polikarpovs can be identified by their lack of exhaust stubs, rounded NACA cowling and lack of cowling shutters, features which were introduced on the Shvetsov M-25 powered Type 5 and later variants (total production 4,500+ units).[8][9] Production started in 1918 and ceased in 1930.