Mitsubishi A6M Zero 0 Fighters, the world’s most maneuverable fighter to date, were made of lightweight duralumin alloy. With a relatively weak 950-horsepower engine, armor plating and self-sealing fuel tanks were deleted to save weight.

Escorting bombers against Chungking China on their first mission in August 1940,  Zero fighters downed 27 Chinese and Russian-made fighters while losing only two Zeros to anti-aircraft fire. After a year in China, an impressive performance led to the belief that the Zero fighters, in the hands of capable pilots, were nearly invincible.