In June 1942, as part of the Japanese Midway operation, the Japanese attacked the Aleutian islands, off the south coast of Alaska. A Japanese task force led by Admiral Kakuji Kakuta bombed Dutch Harbor on Unalaska Island twice, once on June 3 and again the following day.
Tadayoshi Koga, a 19-year-old flight petty officer first class, was launched from the Japanese aircraft carrier Ryūjō as part of the June 4 raid. Koga was part of a three-plane section; his wingmen were Chief Petty Officer Makoto Endo and Petty Officer Tsuguo Shikada. Koga and his comrades attacked Dutch Harbor, shooting down an American PBY-5A Catalina flying boat piloted by Bud Mitchell and strafing its survivors in the water. In the process, Koga's plane (serial number 4593) was damaged by small arms fire.
Tsuguo Shikada, one of Koga's wingmen, published an account in 1984 in which he claimed the damage to Koga's plane occurred while his section was making an attack against two American Catalinas anchored in the bay. This account omits any mention of shooting down Mitchell's PBY. Both American and Japanese records contradict his claims; there were no PBYs in the bay that day. However, his claims do match American records from the attack against Dutch Harbor the previous day (June 3). Rearden noted, "It seems likely that in the near half-century after the event Shikada's memory confused the raids of June 3 and June 4 ... It also seems likely that in his interview, Shikada employed selective memory in not mentioning shooting down Mitchell's PBY and then machine gunning the crew on the water".
It is not known who fired the shot that brought down Koga's plane, though numerous individuals have claimed credit. Photographic evidence strongly suggests it was hit by ground fire. Members of the 206th Coast Artillery Regiment, which had both 3-inch anti-aircraft guns and .50 caliber machine guns in position defending Dutch Harbor, claimed credit, in addition to claims made by United States Navy ships that were present. Physical inspection of the plane revealed it was hit with small arms fireó.50 caliber bullet holes and smaller, from both above and below.
The fatal shot severed the return oil line, and Koga's plane immediately began trailing oil. Koga reduced speed to prevent the engine's seizing for as long as possible.
The three Zeros flew to Akutan Island, 25 miles east of Dutch Harbor, which had been designated for emergency landings. Waiting near the island was a Japanese submarine assigned to pick up downed pilots. At Akutan the three Zeros circled a grassy flat half a mile inland from Broad Bight. Shikada thought the ground was firm beneath the grass, but in his second pass he noticed water glistening. He suddenly realized Koga should make a belly landing. But by then Koga had lowered his landing gear and was almost down.
The plane's landing gear mired in the water and mud, causing the plane to flip upside down and skid to a stop. Although the aircraft survived the landing nearly intact, Petty Officer Koga died on impact, probably from a broken neck or a blow to the head. Koga's wingmen, circling above, had orders to destroy any Zeros that crash-landed in enemy territory, but as they did not know if Koga was still alive, they could not bring themselves to strafe his plane. They decided to leave without firing on it. The Japanese submarine stationed off Akutan Island to pick up pilots searched for Koga in vain before being driven off by the destroyer USS Williamson.