High Quality Content by WIKIPEDIA articles! Gigantor is an American adaptation of the anime version of Tetsujin 28-go, a manga by Mitsuteru Yokoyama released in 1956. It debuted on U.S. television in 1964. As with Speed Racer, the characters` original names were altered and the original series` violence was toned down for American viewers. Originally produced in black and white, the show was colorized and revived in the 1990s.