Chapter 321

Let's Go Play at the Mangaka's House, Part 4 (漫画家のうちへ遊びに行こう その④), originally in the WSJ release, is the fifty-sixth chapter of Diamond is Unbreakable and the three hundred twenty-first chapter of the JoJo's Bizarre Adventure manga.

Summary
Startled by his sudden weight loss, Koichi realizes that a Stand is attacking him, but as soon as he leaves the bathroom to call Josuke for help, he forgets what he was about to do. The next morning, without realizing it, he walks to Rohan's house instead of going to school. This catches the attention of Josuke and Okuyasu. When Koichi arrives, Rohan is working on his manga, and draws a page in just a few seconds. He then turns to Koichi and asks him to "show him the next page of his reality", and after realizing that the information inside Koichi grew significantly after seeing a single panel from his manga, he says that he's getting better as a mangaka and as a Stand user.