Chiyo Mihama, commonly known as Chiyo-chan, is a child prodigy who has skipped five grades to enter 10th grade (the first year of high school in Japan) at the beginning of the series, yet she still excels academically. Such an advancement would be highly unusual in Japan, and the series humorously examines the potential outcomes of this situation. The other characters find Chiyo incredibly adorable but sometimes exploit both her youthful innocence and her academic prowess. Her small stature often leads to a lack of confidence, especially in sports, where she worries about being a burden to others.
Chiyo is frequently the subject of envy among her peers, initially due to her intelligence, but later also because of the revelation that her family is exceedingly wealthy—they own a vast mansion and a summer home, which Chiyo invites her classmates to visit on several occasions. The artistic depiction of Chiyo's pigtails allows for various visual gags in both the manga and anime: Osaka often imagines them as flapping wings or as entities separate from Chiyo herself. At home, she is almost always seen with her large dog, Tadakichi-san. Among all the girls, Chiyo is the only one who does not need to take college entrance exams, as she plans to study abroad, possibly in America.
