Duel Masters (デュエルマスターズ, Dyueru Masutāzu?) is a franchise based on a manga, anime and a trading card game. The English-language version of the series made a truncated three-episode preview premiere on Cartoon Network's Toonami block on February 27, 2004. The episodes then made their "official" premiere on April 13, 2004 on CN's Toonami spinoff block, the Saturday Video Entertainment System (SVES) with fewer edits as well as episodes 4 & 5. Toonami then moved to Saturdays and premiered the rest of the series. "Season 2" premiered on March 26, 2005. Season 3 began production in September 2005.

Source: Wikipedia