The Hiro G2H1 was one of the first long-range land-based bomber/reconnaissance aircraft designed and built for the Imperial Japanese Navy. The prototype appeared in 1933 but suffered from structural weakness. The aircraft was a low-wing, cantilever monoplane powered by two 1,180 hp (880 kW) Type 94 piston engines. The aircraft struggled with the unreliability of the engines, and only eight aircraft were built. The development of the aircraft was costly in both manpower and finance and the aircraft did not live up to expectations. The aircraft however did give the Navy experience in the operation of long-range land-based aircraft, which was to prove invaluable in the later Pacific war.
One aircraft was lost in an accident but the rest operated against the Chinese mainland during the Sino-Japanese incident. In 1937, five aircraft were destroyed in a fire at their base on Cheju Island.