The Ki-61 looked so different than the usual radial-engined Japanese fighters that the Allies at first believed it to be of German or Italian origin, possibly a license-built Messerschmitt Bf 109. The first Ki-61 seen by Allied aircrew had been misidentified as a Bf 109 by USAAF Capt. C. Ross Greening during the Doolittle Raid. In early reports, when it was thought to have been a German fighter, the Ki-61 had been code-named "Mike". The final, and better known code name adopted was "Tony", because the Ki-61 looked like an Italian aircraft.