In 1937 the Japanese Military began the process of designing a new fighter plane to replace the A5M which was then in service in the war in China. Two Japanese companies, Nakajima and Mitsubishi, began work on a new design. The Nakajima company eventually withdrew from the effort as its engineers felt that the size, weight and performance requirements were unrealistic and could not be met. The new aircraft must be fast, agile, with long range and powerful armament, but could only have a 39-foot wingspan in order to meet the requirement that it be flown from Japan’s existing aircraft carriers.
    Mitsubishi's chief designer, Jiro Horikoshi, felt that the requirements could be met, but only if the aircraft could be made as light as possible. In order to achieve the desired weight savings a new top-secret aluminum alloy, T-7178, was developed just for the Zero. The plane would have no armor to protect the pilot or engine and self-sealing fuel tanks were also eliminated. While this made the Zero lighter and more agile than other comparable fighter aircraft, it had a much greater tendency to explode and burn when hit by enemy fire.
    The A6M Zero had a range of almost two thousand miles with drop tanks. Its maximum speed was 331 miles per hour and its engine was rated at 950 hp. While its service ceiling was over 35,000 feet, it was un-pressurized and performed with greatest efficiency below 15,000 feet. It was armed with two 7.7 mm or .30 caliber machine guns and two 20mm cannons mounted in the wings. It could also carry two 130-pound bombs. The 20mm cannons, while powerful weapons, due to weight constraints carried limited ammunition. In contrast, American fighters such as the P-51 and the Corsair each carried six .50 caliber machine guns mounted in the wings.
    Heavily armored American planes could usually take numerous hits of .30 caliber fire and keep flying. By the end of the war the engine horsepower had been raised to 1560 and the wing-mounted machine guns to .51 caliber. This was too little and too late..
    The Zero entered service in July of 1940 in Manchuria. During one aerial battle lasting less than three minutes, 13 Zero’s shot down 27 enemy planes without a single Japanese loss. At the time it had not yet completed testing but its outstanding combat performance in China caused the Imperial Japanese Navy to immediately order the Zero into production. Allied military experts initially did not believe the reports of the Zero’s performance. They would soon become educated. During the Second World War, Zero fighters shot down 1550 American aircraft.
    The A6M is universally known as the Zero from its Japanese Navy designation, Type 0 Carrier Fighter (Rei shiki Kanjo- sentoki), taken from the last digit of the Imperial year 2600 (1940), when it entered service. The American military first encountered the Zero on December 7th, 1941, at Pearl Harbor. The Zero flew cover for the bombers and torpedo planes that attacked the Pacific Fleet. The Zero also strafed Hawaiian airfields and destroyed many American planes on the ground.
    In the initial months of the war the Zero easily outclassed the allied aircraft in the Pacific. With its long range, excellent agility and highly trained pilots Zero’s shot down many older allied aircraft such as the Brewster Buffalo, Bell P-39 and Grumman Wildcat. Its initial success also proved to be its undoing. The Japanese, believing they had a very successful fighter that could handle any allied plane, stuck with the design through the entire war, making only superficial changes to its engine and armament. American fighters were continually updated and replaced with newer designs. The P-51 Mustang, F6F Hellcat and the F4U Corsair were 100 mph faster, could climb higher and with six .50 caliber machine guns, were more heavily armed.
    Japanese culture also played a role. As dying for the Emperor was considered an ultimate honor, the Japanese did very little to provide for pilot protection or recovery of downed pilots. No armor, no self sealing fuel tanks and a very light airframe. A few .50 caliber hits from a Corsair, Hellcat or Mustang often turned a Zero into a ball of flame. The Japanese also did not put much effort into recovering downed pilots, believing a shot down pilot had failed in his duty. They did not realize or consider that a trained fighter pilot, at his most basic level, is an expensive and valuable commodity. Not everyone can be a fighter pilot and it takes lots of time and money to train one. A shot down American pilot could often return to duty and fly again; downed Japanese pilots were usually lost forever.
    In June of 1944 the Japanese attempted their last big offensive. This culminated in the Battle of the Philippine Sea, also called the Great Mariana’s Turkey Shoot. In this engagement the Japanese lost three aircraft carriers and over 600 planes. These incredible losses were the result of the obsolescence of the Japanese aircraft and the inexperience of the Japanese pilots.
    By 1945, the Zero was relegated to the status of flying bomb. Allied air superiority, faster more numerous aircraft, and experienced Navy and Marine combat pilots left the Japanese with only one effective tactic to sink American ships. Pilots with minimal training were sent aloft to crash their bomb-laden planes into U.S. Navy ships. The Kamikaze was born. During the battle of Okinawa, 1465 Japanese planes, many of them Zero fighters, were lost attempting to hit U.S. Navy ships. These attacks sank several dozen smaller U.S. Navy ships and killed over 5000 U.S. sailors. Between 1939 and August, 1945, 10,500 Zero fighters were built by Japan. During the same time period 12,571 Corsairs, 15,018 Mustangs, and 12,275 Hellcats were produced by the United States. Only two AM6 Zeros are believed to be still flying.