TV-Series
Description
Jinko Sasajima is a first-year student at Buzō Prefectural High School and serves as the technical member of the school's quiz circle. She is the younger sister of Gakuto Sasajima, the captain of the Buzō quiz club, though people often note that they do not look very much alike for being siblings.

In terms of appearance, Jinko has blonde, chest-length hair that she typically ties up into twin tails, with bangs hanging over her forehead. She has dark brown eyes and is considered a pretty girl by many of her peers. Her typical attire often includes a short-sleeved uniform shirt paired with a blue track jacket and track pants folded just below the knee, worn underneath her school skirt.

Jinko has a distinctive and eccentric personality. She does not place much importance on formalities and maintains a positive outlook, often stating that competitions are enjoyable precisely because no one can predict the outcome. One of her most notable traits is her strong curiosity about how things work, particularly concerning electronics. On one occasion, she dismantled the quiz buttons belonging to another school simply to examine their internal mechanics. She also speaks with a distinct accent, which originates from her childhood years spent living in Kyoto. Unlike her brother, who has abandoned the accent, Jinko has made no effort to change the way she speaks.

Jinko's primary role in the story is not as a competitor in quiz matches. Instead, she supports the Buzō quiz circle by using her skills and passion for mechanics. She is responsible for creating the buttons that the team uses for practice, working to build them at a lower cost than commercially available equipment. Her interest in this field is introduced when she unknowingly leaves a book about electronics behind after meeting the protagonist, Shiki, in the library. Initially, she is introduced as a mysterious girl riding on the back of her brother's bicycle. She later meets Shiki in his usual library spot, and weakened by hunger, she accepts food from him, beginning their acquaintance. Her role is that of a technical creator and a source of positivity for the group, contributing her practical abilities and cheerful demeanor to the team's overall dynamic.