Sayaka is a minor character who always appears alongside her friend, Akari Iguchi.
Sayaka seems very bold and uninhibited; however, she may rather be more mature about matters that teenagers tend to obsess over. Thus in chapter 95 when Tomoko torments her friend Akari over her belief that Akari asked to see Tomoki's genitals, Sayaka frankly responds, "Even girls are interested in those kinds of things, it's not weird at all!"
Sayaka has loose, black shoulder-length hair.
Season 1: Episode 3
Akari and Sayaka have been close friends since middle school. Sayaka is often seen with Akari, usually encouraging Akari to interact with Tomoki.
Sayaka first really meets Tomoko in chapter 95 having only seen her from a distance during the sports festival. Realizing she is Tomoki's older sister, she insists on meeting her despite Akari's objections. Tomoko naturally directly asks Akari, "are you here to ask me about dicks again?" To Akari's horror and Tomoko's surprise, Sayaka asks Tomoko, "What's wrong with wanting to see the genitalia of the person you like?"