 The Japanese publisher Shogakukan has been releasing the individual chapters in "tankōbon" format with the first one being released on August 8, 1997, and currently, 53 "tankōbon" have been released.The distributing company Viz Media has licensed the series for English in the United States.Viz released the first seven volumes of the series in "tankōbon" format from July 6, 2000 to January 2003 as well as in magazine format.