The Mitsubishi A7M Reppuu (烈風, "Strong Gale") was a carrier-based fighter intended to be the successor to the legendary A6M Zero. Like its predecessor, it was designed by Horikoshi Jirou. While superior in every aspect to the Zero, a combination of the design team being diverted to other projects, earthquake damage and bombing raids on the Mitsubishi factory prevented it from ever going into mass production; ultimately only 9 examples were made and none saw combat. It's Allied reporting name was "Sam".
Ace pilot Sakai Saburou, who was a test pilot for the Reppuu, said that it could literally fly circles around a P-51 Mustang or F6F Hellcat, even while climbing.