This is the earliest complete surviving Toei Superhero series of the 1960s. (Arâ no shisha (1960), the actual first Toei Superhero Series of that decade, premiered a month earlier, but unfortunately, that series, save the first episode, is currently lost.)
While not as popular in its native Japan as Toei's more popular superhero rosters (like Kamen Rider and Super Sentai), this series has nonetheless developed a strong cult following in Brazil, where it aired on the network TV Record in 1964.
National Kid, the eponymous superhero of this TV series, is named for the "National" electric products brand by the series' main sponsor, Matsushita Electronics (known today as Panasonic).
National Kid's weapon, the Eroruya Ray Gun (Eroruya Kousenjuu), was based upon the gun-like flashlight sold by Matsushita's "National" electronics line. He usually carries two of these.