Zone Fighter, known in Japan as Ryusei Ningen Zone, is a tokusatsu science fiction superhero television series. Produced by Toho Company Ltd., the show aired on Nippon Television from April 2 to September 24, 1973, with a total of 26 episodes, it was cancelled due to the oil crisis of 1973. This was Toho's answer to not only the popular Ultra Series, but the Henshin Hero phenomenon started by shows like Kamen Rider and Android Kikaider. The previous year, Toho had just made their successful first superhero show, Rainbowman. The series was also notable for its guest appearance by Toho's own Godzilla, as well as two other Toho monsters, King Ghidorah and Gigan. Supplementary materials published by Toho have confirmed Zone Fighter to be part of the Showa-era Godzilla series, taking place in between Godzilla vs. Megalon and Godzilla vs. Mechagodzilla.