The episodes began airing on October 3, 2006 in Japan on TV Tokyo. The first season of the anime, known as the "1st stage", aired for 51 episodes, finishing its run on September 25, 2007. The second season, known as the "2nd stage", began airing on October 2, 2007, and finished its run on September 30, 2008, lasting 52 episodes. The English adaptation of the series has been licensed by Funimation, and the first season of the anime is set to air in the beginning of 2009.