Moero! Kamen Rider!
It was the sunset of the 70s and the sunrise of the 80s. Disco was becoming extremely popular in Japan, and the toku music scene reflected this. (see Battle Fever J or Denjiman for more proof.) This was the first OP used, sung by Ichiro Mizuki and Koorogi '73.
AKA Magmaman. I personally feel this is one of Masato Shimon's greatest performances ever. Composed by Shunsuke Kikuchi, who did Kamen Rider 1-Skyriders theme songs.
Famous for his work on the Kamen Rider series and the Jet Jaguar theme song, Shimon was the king of 70s Japanese TV songs. Here he is in 1976 singing his hit single "Oyoge! Taiyuki-kun!" that is STILL the best selling single in Japan after all these years due to a CD release. It earned him a Guinness World Record. Shimon said he had no comment on the success. Well deserved, Shimon-san.
Theme performed by Ichiro Mizuki, Koorogi' 73, and the Tokyo Boys Choir.
The show itself could be best described as a bunch of Super Robot anime crossed with Johnny Sokko/Giant Robo.