Toei Animation

Toei Animation is an animation studio owned by Toei Company after purchasing its earlier incarnation, Japan Animated Films in 1956. The studio is known for its large number of TV series, movies, and anime adaptations of manga created by famous Mangaka like Shotaro Ishinomori, Go Nagai, Akira Toriyama, the early works of Hayao Miyazaki. It also helped propel the Magical Girl and Super Robot genre's popularity including Mazinger Z and its sequels.

Dynamic Productions
Several of Go Nagai's manga made the transition to anime, but rather than full adaptations, they were given more original stories to fit the general audience.
 * Devilman (1972-1973)
 * Mazinger Z (1972-1974)
 * Great Mazinger (1974-1975)
 * Grendizer (1975-1977)
 * Dororon Enma-kun (1973-1974)
 * Cutie Honey (1973-1974)
 * Cutie Honey Flash (1997-1998)
 * Getter Robo (1974-1975)
 * Getter Robo G (1975-1976)
 * Getter Robo Go (1991-1992)
 * Steel Jeeg (1975-1976)
 * Gaiking (1976 - 1977) (By technicality)
 * Majokko Tickle (1978-1979)

Legal Disputes
By the events that lead to Go Nagai being uncredited as the original creator of Gaiking, a legal battle broke out between Dynamic Pro and Toei Animation. Toei admitted that Go Nagai was left out of the credits to avoid paying royalties. With the battle lasting more than a decade, Nagai had ceased any further collaborations with Toei. However after about 40 years, Toei gained the rights to produce a Mazinger Z movie.