the final year of the Pacific War. Army fighter units equipped with this model included the 5th, 17th, 18th, 20th, 59th, 111th, 112th, 200th and 244th Sentai, and the 81st Independent Fighter Company. Pilots were trained at the Akeno and Hitachi (Mito) Army Flying Schools. Many Akeno and Hitachi instructors were from operational units and between training sorties they also flew combat missions, making the most of the few fighters that were operational, but these wings were only partially re-equipped. During interception of high-flying B-29 Superfortresses (before the B-29s switched to low-level missions) the new fighters struggled as the engine's performance still dropped off at high altitudes. The most effective strategy against the B-29 Superfortress remained the exceedingly dangerous head-on attack, which left the fighter relatively stationary in the sights of the bomber's defensive guns, making it an easy target. In this type of combat, the Navy's Mitsubishi J2M Raiden remained superior. 111th Sentai Ki-100s intercepted B-29 Superfortresses attacking Kobe on 5 June 1945, claiming six bombers shot down and five 'probables'. The Americans recorded a loss of nine B-29s, including those downed by Ki-100s over the target area. Ki-100s of the same unit joined by 244th Sentai Ki-84s in a large-scale engagement against 506th Fighter Group P-51 Mustangs over Nagoya Bay on 16 July 1945. The Ki-100 pilots claimed six P-51s and in return, five Ki-100s were lost, with three pilots killed, although American records only show one loss. On 25 July 1945, 18 244th Sentai Ki-100 fighters clashed with 10 VF-31 Grumman F6F Hellcats from the light aircraft carrier in an air battle where the Ki-100 pilots claimed 12 victories with two losses. Claims and counter-claims for this action remain contentious. The Americans claimed two Ki-100s and admitted to losing two VF-31 F6F-5 Hellcats. These include a Ki-100 and a Hellcat which collided, killing both pilots. After the bombing of the Kagamigahara plant and the slow deliveries of components by satellite plants, the production rate of the Ki-100 declined, and between May and July, only 12 were delivered. Bombing would end production with only 118 of the Army Type 5 Fighter Model 1b having been delivered. The final flights made by the Imperial Japanese Army Air Service were made by two Ki-100s ferried from Komachi to Yokosuka, where they were handed over to the United States, who then shipped them back to the US for evaluation. Variants Ki-100