The Mitsubishi A6M Zero was a Japanese single-seat fighter aircraft used extensively by the Imperial Japanese Navy Air Service (IJNAS) during World War II. It was known for its speed, its maneuverability, and its long range, making it a formidable adversary for Allied fighters in the early stages of the war. It was powered by a radial engine and was armed with machine guns. The Zero’s early dominance in the Pacific theater was countered by Allied development of more powerful fighter aircraft.