Junichi makes his first appearance in "HUMANCENTiPAD", where he is the front of the HUMANCENTiPAD, a new device by Apple containing three people attached to each other mouth-to-anus. Like Kyle Broflovski and an unnamed woman, he is part of it because he did not read the Terms and Conditions of the last iTunes update.
Junichi also appears in "City Sushi" as the new owner of the City Sushi stand. Tuong Lu Kim, owner of City Wok attempts to kill him at great lengths, much to Takiyama's anger, but after discovering Lu Kim's true identity, Takiyama ends up committing suicide for mistaking a white man for an Asian, jumping off the Tower of Peace.
Takiyama continued to be seen in the Season Eighteen intro, along with his restaurant. He appears on-screen again in "South ParQ Vaccination Special", attending Margaret Nelson's funeral, indicating his suicide attempt three seasons earlier was unsuccessful.
Junichi has the stereotypical characteristics of Asians seen in the series such as small eyes., although his eyes are not as closed and squinty as Tuong Lu Kim's eyes. He has black hair. He wears a white gi and black pants.
Junichi was shown to be very kind in his first appearance; he refused to eat any food to spare Kyle and the unnamed woman from "HUMANCENTiPAD" from eating his feces, only giving in due to hunger and extremely tasty food. He was also shown in "City Sushi" trying to make amends with Lu Kim despite their rivalry. He also made no attempts to hurt or humiliate Lu Kim during their peace treaties, although Lu Kim betrayed him several times. Junichi was extremely gullible or trusting, as he believed Lu Kim when he said he wanted to make peace with him, telling him to meet him on The Tower of Peace even after reading a letter from Lu Kim almost calling him a Japanese Dog, and trusting him a second time after Lu Kim betrayed him at the school assembly.
- Junichi's first name is derived from Trey Parker's former college roommate, Junichi Nishimura.
- "City Sushi"
- "South ParQ Vaccination Special" - Seen at the end celebrating the end of the pandemic.
- ""South Park" City Sushi (TV Episode 2011)". IMDb.com.