Torishima Kazuhiko was a new editor at the manga magazine Jump when he worked with Toriyama Akira. In an interview with ITmedia, he described how the manga Dr. Slump came about. The two made manga and crushed them, made them and crushed them, again and again. It took about a year and a half.
Torishima recalled what Toriyama told him later. When Toriyama moved house, about 500 pages of drafts that Torishima had rejected came out of his closet.