The sequel to Nagai Gou's anime/manga Mazinger Z.
Great Mazinger (グレートマジンガー, Gurēto Majingā) is a science fiction manga and super robot mecha anime that features a new robot that is an improved version of the original Mazinger.
It was aired on Japanese television in 1974, immediately following the end of the first Mazinger series, and ran for 56 episodes.
This tag implicates mazinger_(series) (learn more).