On April 28 moved to Itami, Osaka where they started training with five Kawasaki Ki-61 "Hien" and two Nakajima Ki-43 "Hayabusa" they received from Akeno. All pilots of the unit except Sentai-cho (Regiment Commander) Major Furukawa Haruyoshi and Hikotai-cho Capt Ogata Junichi were fresh from the schools with no experience whatsoever. Due to maintenance problems there were many accidents with the Hien which received the nickname “Killer Plane”.
On May 20 the unit moved to Komaki airfield, Nagoya, where they continued training. From the end of June they begun night flight training.
In July the unit became part of the 11th Hikoshidan (Air Division), were assigned the air defense of Chukyo Area (Nagoya-Osaka) and performed daily patrols against B-29s at 8,000m.
From the middle of June 1944, B-29s based in China started arriving over North Kyushu. On August 21 the unit came under the Seibu-Gun (Western Area Army). On that day the unit strength was 17 Hien and in the same month the unit moved to Tachiarai airfield. September 1 the unit was relocated in Jeju Island (Saishu in Japanese), Korea for advanced interception of B-29s.
October 25 signified the first air battle of the unit against B-29s. Following reports from the China Army that over 100 B-29s are heading towards Northern Kyushu, 17 Hien of the 56th scrambled but they took-off too late and missed the US bombers on their way to the target. They caught them on their way back, after they had bombed Oomura, shooting down one B-29 and damaging six while eight of their own received damages.
On the next day one B-29 arrived over Oomura to asses the damage and three Hien from the 56 took-off again to intercept but all of them failed to return. Two of the planes including Hikotai-cho Ogata were forced to make a belly landing escaping with their lives while the third plane was probably lost over the sea.
On November 15 the unit relocated back to Itami via Tachiarai but 5 days later the unit with 14 Hien relocated yet again to Tachiarai to participate in the Ko-I-Go Operation.
On November 21 the unit shot down three B-29s and on December 1 three pilots were assigned to a Tokotai unit.
Following reports that B-29s were going to attack the Osaka area, the unit relocated yet again in Itami. On December 13 the first B-29 air raid was contacted over the Nagoya area flying higher than 9,000m well above the normal service ceiling of the Hien. Following modifications including the improvement of the oxygen system for the pilot, the removal of the bullet proof protection of the oil tanks as well as the removal of the wing 20mm cannons, the airplanes became light enough to reach that altitude.
During the December 18 interception the unit managed to shoot down two B-29s and damage two more.
56th Sentai tail marking illustrated by Devlin Chouinard.
On January 3 1945, the unit intercepted again B-29s over the Nagoya area shooting down two enemy planes damaging many. One pilot 1st Lieut Wakui crashed his plane on a B-29. One more pilot Sgt Takamukai crashed his plane too, lost the tip of one of his wings and was shot numerous times but managed to return to base.
On March 14, B-29s bombed Osaka. Due to heavy clouds only experienced pilots scrambled including Sgt Takamukai. Unfortunately immediately after take-off he crashed on a factory chimney near the airport.
On March 17 during an air raid against Kobe Sentai-cho Ogata and two other pilots were lost.
On March 31 the unit was assigned to the 12th Hikoshidan to participate in the battle for Okinawa and with 27 planes moved to Ashiya airfield in North Kyushu for air defense duties. On April 29 the unit relocated to IJNAF’s Saeki airfield.
On May 4 US forces attacked the Japanese bases including Saeki airfield. More than a dozen Hien were lined up on the landing strip but with the help of Navy personnel, three managed to take-off. Soon after, B-29s arrived at a height of about 5000m and started pounding the airfield. Five planes were burned and five destroyed on the ground. The unit also suffered seven dead and five seriously injured. As a result the Sentai was left with only the 3 planes that managed to take-off.
On May 20 unit returned to Itami to reorganize and get new planes making a stop at Ashiya where they changed to Hien Model 2.
On July 9, 1945 the unit had their first aerial encounter with P-51s loosing three pilots. From that time on the unit stopped daytime operations.
In the end of July the unit had 20 planes and 48 pilots in their strength. Until the end of the War the unit shot down 11 B-29s losing 33 of their own including ground crew members.