Sheer Heart Attack, Part 9 (シアーハートアタック その⑨, Shiā Hāto Atakku Sono 9), originally You've Matured! (成長したな!, Seichōshita na!) in the WSJ release, is the ninety-seventh chapter of Diamond is Unbreakable and the three hundred sixty-second chapter of the JoJo's Bizarre Adventure manga.
Summary
While Josuke and Okuyasu take a shortcut toward the shoe shop, Kira has punched a gaping hole through Koichi's chest. He has one minute to leave, but is distracted by one of Koichi's inside-out socks and loses time fixing it. Now ready to turn Koichi into a bomb, he is then interrupted by Jotaro who managed to regain consciousness but is still bleeding profusely.
The two men confront each other, Kira being fairly confident against an injured opponent while Jotaro only taunts him. Killer Queen attacks with a punch, but Star Platinum violently punches him first with an overhead, stunning Kira. Jotaro proceeds to pummel Kira away, taking him down. Jotaro warmly praises Koichi before fainting again. Josuke and Okuyasu arrive at the shoe shop and see the three persons laying on the ground.