Probably the best-known Axis aircraft of World War II was the Mitsubishi A6M Zero fighter. The Zero, which first engaged in combat in 1940 over China, flew from Japanese aircraft carriers and land bases through the end of the war. When the Japanese struck Pearl Harbor on 7 December 1941, 78 Zeros were among the 360 aircraft launched in the sneak attack, with another 39 Zeros retained on board the carriers for combat air patrol.
When the war began, the Zero was unquestionably the best-performing fighter aircraft in the Pacific area. It was the world’s first ship-based fighter since the Sopwith fighter series of World War I that was superior to its land-based opponents. In the hands of experienced Japanese pilots the Zero was a match for any other fighter in the Pacific war until mid-1943 when the Grumman F6F Hellcat entered combat.
Under chief engineer Jiro Horikoshi, the Zero was designed in response to a Navy requirement for a long-range fighter to escort naval bombers. The Zero was a low-wing, all-metal monoplane, with fully retractable main landing gear. It was carrier capable, with most models having the outer portion of each wing—just over 18 inches—fold to permit them to fit on carrier elevators. (In some models the wingtips were simply removed.) The standard models had two 7.7-ram machine guns in the fuselage and two 20- mm cannon in the wings. Some A6M3 models were evaluated with two 30-mm cannon, and in later models there was one 7.7-mm and one 13.2-mm machine gun. Toward the end of the war the A6M5 night-fighter variant also had a fuselage- mounted, oblique-firing 20-mm cannon to intercept attacking B-29 Superfortress bombers. The early Zeros could carry two 132-pound bombs or one 551-pound bomb.
During its long production run numerous updates were made to the aircraft. The later A6M5 Model 52 production aircraft had a maximum speed of 351 miles per hour, could reach 19,700 feet in seven minutes, and had unequaled maneuverability.
The prototype A6M1 first flew on 1 April 1939; after minor teething problems were solved, the aircraft met or exceeded all Navy requirements. Fifteen preproduction A6M2 variants were used in combat over China from August 1940. Mass production followed, with a total of 10,449 aircraft produced by Mitsubishi and Nakajima plants.
The Zero entered combat over China on 19 August 1940, when 12 of the new fighters escorted 32 Navy bombers from Hankow on an attack against the temporary Chinese capital of Chungking. No Chinese interceptors were encountered. Nor was there any aerial interference with the succeeding Zero escort missions until 13 September, when 13 Zeros encountered 30 Chinese fighters over Chungking. Twenty-seven Soviet-built 1-15 and 1-16 fighters flown by Chinese pilots were shot down without loss to the Zeros. Through September 1941, Zeros shot down or destroyed on the ground 99 Chinese aircraft at a cost of only two Zeros lost to ground fire. On those missions the Zeros regularly made round-trip flights up to 1,000 miles.
U.S. military leaders learned of the Zero soon after it entered combat in China, and the wreckage of several Zeros was recovered at Pearl Harbor. During the Midway operation in June 1942, two Japanese carriers, the Junyo and Ryujo, launched air strikes on the morning of 3 June against the U.S. base at Dutch Harbor in the Aleutian Islands. During the second Japanese strike of the day a Zero fighter was damaged over Dutch Harbor, apparently by machine-gun fire from a PBY Catalina flying boat that was being shot down. The Zero’s pilot, Flight Petty Officer Tadayoshi Koga, made a forced landing on Akutan Island, 25 miles east of Dutch Harbor. The island had been designated as an emergency landing site for crippled carrier planes; a submarine was to pick up pilots forced down there.
The ground was not grassland, as Koga surmised, but mud and water. As the plane landed, it flipped over. Twenty- year-old Koga was killed, apparently from a snapped neck or smashing his head on the instrument panel. The two other pilots in his section followed his aircraft to Akutan and, despite orders to strafe and destroy any aircraft that came down on land, just circled, hoping that Koga was alive. Finally, believing a submarine would rescue their downed comrade, the two pilots returned to the Ryujo. A Japanese submarine approached Akutan, but was scared off by a U.S. destroyer-seaplane tender that detected and attacked the underwater craft.
A month later, on 10 July, a U.S. Catalina commanded by Lieutenant William Thies overflew Akutan and saw Koga’s Zero, flipped over and on its back but virtually intact. Immediately a search party was sent to examine the aircraft, followed by a salvage party that recovered the first flyable Zero to fall into U.S. hands.
After being shipped back to the United States, Koga’s Zero was reassembled and checked out. U.S. Navy pilots began flying the aircraft on 20 September 1942. Lieutenant William N. Leonard, a U.S. Navy pilot and fighter ace who flew Koga’s Zero, recalled,
the Zero 21 was a mighty sweet machine. . . . The refined aerodynamic design was not compromised by mass production. Fit and finish of all plates, rivets, the close and accurate fit of fairings, engine cowl, access plates, canopy, and wheel doors was most faithfully executed.
The propeller spinner faired into a cowling that smoothed the contours of the reduction gear housing of the engine. The interior aerodynamics of the engine cowling permitted the adequate cooling of the two-row 14-cylinder engine with a remarkably small intake.1
Sometimes the Zero was flown in mock combat against U.S. fighters. The Navy pilots quickly uncovered the aircraft’s secrets, and details of its flight characteristics were quickly sent to U.S. pilots in the Pacific. Later stories circulated that the lessons learned from Koga’s Zero were applied to the design of the F6F Hellcat. But that is strictly urban myth, as the Navy had ordered the first XF6F-1 on 30 June 1941, and that aircraft flew on 26 June 1942. Large Hellcat production orders had already been placed in May 1942—before Koga’s Zero had crashed.
Rather, the lessons learned from the fighter helped the F6F pilots. The evaluation of Koga’s Zero—wearing U.S. insignia—continued until mid-February 1945. While the aircraft was taxiing at the San Diego naval air station, the plane was overrun by an SB2C Helldiver, whose propeller chopped the Zero into pieces. The Zero pilot escaped.
The Japanese Navy flew Zeros throughout the war—as fighters, as dive bombers, and, finally, as kamikazes. Replacement fighter aircraft, significantly more capable, were never available in adequate numbers and certainly never achieved the fame of the Zero.
Although more Zeros were captured during the war, and scores were taken by the victors when the war ended, it was the A6M2 flown by Tadayoshi Koga that made a difference in the Pacific war.
1. Quoted in Jim Rearden, Cracking the Zero Mystery (Harrisburg, PA: Stackpole, 1990), 95.
Also see R.J. Francillon, Japanese Aircraft of the Pacific War (London: Putnam, 1970), 362-377.