How a Japanese fighter plane downed in the Aleutians unlocked secrets that turned the tide of World War II

Part of a continuing weekly series on Alaska history by local historian David Reamer. Have a question about Anchorage or Alaska history or an idea for a future article? Go to the form at the bottom of this story.

On June 4, 1942, 19-year-old Flight Petty Officer Tadayoshi Koga launched his Mitsubishi A6M Zero Japanese fighter plane off the deck of the carrier Ryūjō in the earliest days of Japan’s Aleutian Island campaign. Koga was part of a three-plane group that relentlessly strafed Dutch Harbor for the second consecutive day. On this particular flight, they were the likely culprits that downed an American PBY Catalina and then circled back to shoot the survivors in the water.

During one of Koga’s passes over the American forces, his Zero took several hits, of which one cut the oil line from his engine. Trailing oil and smoke, he flew northeast to Akutan Island for an emergency landing. There he saw what he thought was a smooth green field. Already slowed to prevent his engine from seizing, he descended and lowered his landing gear.

Too late, he realized that the smooth green field was, in fact, a bog. If he had kept the landing gear retracted and belly-landed the plane, he might well have survived. Instead, the wheels caught in the mud, flipped the plane, and instantly killed Koga. However, his wingmen did not know that he was dead, only that he did not emerge from the plane. Though under orders to destroy any Zeros left in enemy territory, they chose to leave it intact and return to the Ryūjō. This article is the story of that plane, the Akutan Zero, that helped turn the tide of the war.

Some of the details are a little fuzzy, understandable since the events took place amidst the fog of a war that ended more than 75 years ago. For example, no one knows for sure who placed the fateful holes in the Akutan Zero. Soldier Lee Compere claimed he hit the plane four times out of four shots from the ground. Decades later, he told the Army Times, “I was, with almost everyone else, in my foxhole near the top of a hill (when) the Zero came over our barracks area at Fort Mears (at Dutch Harbor on Amaknak Island).” “I had previously loaded my M1 rifle with alternating tracer and armor-piercing bullets,” said Compere, “and I cut loose with all I had at that Zero.” He believed these shots put the Zero into the ground, a possible, if incredibly improbable, claim.

At the dawn of World War II, the Zero was perhaps the preeminent dogfight aircraft in the world, a brilliantly designed combination of machinery that emphasized simplicity, responsiveness and ease of repair. It was more agile than British Spitfires, outfought American fighters like the F2A Buffalo and F4F Wildcat, and had far greater range than the German Messerschmitt Bf 109. From 1940 to 1942, the Zero outflew whatever planes Allied forces threw at them. The Japanese fighter ruled the skies over Pearl Harbor and decimated Allied planes of every type across the Pacific. Such was its reputation that American military personnel imbued the Zero with almost mystical capabilities. Quite simply, the Zero heavily contributed to Japan’s early victories in the war.

William Leonard, a fighter ace during World War II who retired as a rear admiral, described what it was like first encountering the Japanese fighter on the Pacific front. “We were learning the folly of dog fighting with this new-to-us (Zero) and the merit of high-speed and altitude advantage if we could get it.” He added, “From the way the Zero pilots rollicked about the sky, at times it looked as though they would rather stunt than fight.”

Even after the Zero had been extensively studied, some in the American military refused to believe the Zero had been an entirely Japanese project. Due to a mixture of arrogance and racism, some of these doubters thought the fighter was based in large part on some European plane. While the Zero was built upon preexisting engineering knowledge from around the world, the design was ultimately a Japanese one.

By the time of the Dutch Harbor attacks, the full capabilities and limitations of the Zero remained largely a mystery to American forces, though that would soon change. A month after Koga’s death, his plane remained undiscovered. Finally, on July 10, 1942, a gunner on a Navy Catalina spotted the downed Zero. The Catalina’s commander, Lt. William Thies, confirmed the sighting and convinced his superior officer to approve a closer inspection. It was only on his return to the crash site that Thies realized that the fighter was one of the renowned Zeros.

Thies’ copilot, Ensign Robert Larson, later recalled, “We were surprised at the details of the airplane. It was well-built, with simple, unique features. Inspection plates could be opened by pushing on a black dot with a finger. A latch would open, and one could pull the plate out. Wingtips folded by unlatching them and pushing them up by hand.” He also noted, “The pilot had a parachute and life raft, somewhat discrediting the then common theory that Japanese pilots weren’t interested in survival.”

Any Alaskan who has just attempted to cross muskeg on foot will sympathize with the plight of the salvage crews, who had to remove a fighter plane partially buried in knee-deep mud and transport it to the island’s coast for pickup. It took three separate salvage attempts before they could bring the Zero back to Dutch Harbor.

From there, the Akutan Zero was shipped to San Diego, where it was quickly repaired. On Sept. 20, it was back in flying condition, after a month in an Aleutian bog and three and a half months after being shot down. That day, Lt. Commander Eddie Sanders made the first test flight. His subsequent report stated, “The very first flight exposed weaknesses of the Zero which our pilots could exploit with proper tactics.” In essence, while quick and agile, the Zero lost much of its maneuverability at speeds above 200 knots. In addition, the fighter rolled more easily to the left than the right, and the engine was susceptible to shutting off under negative acceleration. When combined, these flaws suggested a straightforward tactical remedy.

As Sanders noted, “We now had the answer for our pilots who were being outmaneuvered and unable to escape a pursuing Zero: Go into a vertical power dive, using negative acceleration if possible to open the range while the Zero’s engine was stopped by the acceleration. At about 200 knots, roll hard right before the Zero pilot could get his sights lined up.”

These tactical innovations accentuated the Zero’s other flaws, namely the lack of armor that made it so fast and nimble in the first place. The discoveries made by Sanders and others were quickly relayed to pilots on the front, where they made an immediate impact. Marine pilot Lt. Col. Kenneth Walsh, credited with 21 destroyed enemy planes during World War II, survived to earn his first kill thanks to such intelligence. Said Walsh, “Knowing what to do with a Zero on my tail — information that came from Koga’s Zero — saved my life several times.”

The fighter ace William Leonard claimed, “The captured Zero was a treasure. To my knowledge, no other captured machine has ever unlocked so many secrets at a time when the need was so great.” Japanese military historian Masatake Okumiya wrote that the revelations from the Akutan Zero were as dire for the Japanese military as the loss at the Battle of Midway.

By the end of the war, the reputation of the Zero had cratered. Attrition of the Japanese fighter ranks had removed many of their pilots. And intelligence gained from captured Zeros combined with technological improvements by American and British flipped the aerial superiority to such a degree that some military historians have questioned the virtues of the Zero at any point in time. Similarly, some historians and military minds disagree on the extent of the Akutan Zero’s importance. Still, there is no doubt that its discovery was an intelligence coup with an immeasurable impact.

The Akutan Zero did not make it to the end of the war. A February 1945 runway accident left the fighter in pieces. But bits of the wreckage survive in several museums, including the Alaska Aviation Heritage Museum in Anchorage. As for Koga, Thies’s party originally buried him on Akutan Island. His body was exhumed in 1947 and reburied on Adak Island. His body was almost certainly exhumed again in 1953 and returned to Japan, where it was likely cremated.

If you want to know more about the Akutan Zero — including Zeros in general or Tadayoshi Koga in particular — I highly recommend Jim Rearden’s 1995 book, “Koga’s Zero: The Fighter That Changed World War II.” It is affordable and widely available.

Key sources:

Dorr, Robert F. “Crash Recovery Helps Navy ‘Zero’ in on Air Supremacy.” Navy Times, October 4, 2004, 43.

Dorr, Robert F., and Fred L. Borch. “WWII Veteran Says He Shot Down ‘Akutan Zero.’” Army Times, December 18, 2006, 43.

Rearden, Jim. Koga’s Zero: The Fighter That Changed World War II. Missoula, MT: Pictorial Histories Publishing Company, Inc., 1995.

Smith, Peter C. Mitsuboshi Zero: Japan’s Legendary Fighter. Barnsley, UK: Pen & Sword Books Ltd., 2014.