Quick answer — Hisanori Koyatsu voices Kouhei Iwamoto in The Gokusen, Yamada in My-Otome.
Hisanori Koyatsu voices Kouhei Iwamoto (The Gokusen), Yamada (My-Otome).
Kouhei Iwamoto is voiced in Japanese by Hisanori Koyatsu.
