|School||Kaimei High School, Class 1-E|
|Manga Debut||Oneshot (Weekly Jump version)|
Ichirō Yamanaka (山中 一郎, Yamanaka Ichirō) is a student from the original oneshot who asks the Sket Dan to find out why his girlfriend suddenly dumped him. It turned out that he had mentally convinced himself that his girlfriend Namiko was actually her deceased twin sister Nanako, who he had been dating since middle school. Once he is confronted about it, he says goodbye to Nanako properly and decides to move on with his life.
Ichirō previously attended Kishida Middle School and appears to be on the baseball team.
Ichirō has a serious and diligent personality, he is actually an introvert.