Yabumi Juunichou (十二町 矢文, Juunichou Yabumi) is a junior of Class 10 and the chairwoman of the Library Committee.
Juunichou often quotes the numerous books she has read, adding them into her dialogue as she feels is suitable. Juunichou has something of a sadistic sense of humor, jokingly telling the Student Council interns to go home, even though they were in their underwear. She can keep a cool head under pressure, making an educated guess about a copy of a book she had not read. Juunichou is a good loser, accepting that she had been outwitted with grace. Juunichou seems quite familiar with her fellow chairmen, recognizing how both Kiruko Tachiarai and Aoki Aka work.
Juunichou has long, flowing, dark blue hair that even somewhat covers her brown eyes. She wears a modified version of a regular Hakoniwa uniform with the white jacket open and a revealing yellow shirt that shows off her large chest. She wears a dark blue miniskirt, black tights, and light blue shoes. On her left arm is a yellow armband, showing her position as a Library Committee Chairwoman. Ten years later, Juunichou wears a black suit.
Kurokami Medaka's Successor Arc
After solving the first trial, everyone except Kouki Akune and Zenkichi Hitoyoshi arrives at the base of the Clock Tower. Inside the first floor, Junnichou awaits them. She reveals that all the other Chairmen have gathered in the clock tower to test the Student Council and the Candidates. She says they must past the trial the chairmen will give them and starting her own trial the "Reading Showdown." In this trial, each contestant will be given the opportunity to give one question to Juunichou, betting a item of theirs on the line. The questions must be based on a book or piece of literature. If Juunichou answers correctly they lose that item but can make a new question if they bet another item. If Juunichou answers incorrectly, the entire group passes the trial.
As each Candidate comes up and asks a question, Juunichou shows her vast knowledge and answers all correctly. Eventually the Candidates were stripped down to their underwear since they bet their clothes. Suishou Kibougaoka states that both Misogi Kumagawa and Mogana Kikaijima were crazy enough to bet their clothes which they lost because Kikaijima give easy questions and Kumagawa cheated by not even knowing the answers to his own questions. Shori Wanizuka notices the book Ima Takarabe has and asks to bet everything they have and have lost on one question. Kumagawa notices this was a good blitzkrieg strategy. Wanizuka reveals that the book was a manga, and asks if a manga was ok. Juunichou accepts the manga, saying that even the people who are well versed in literature read manga. Wanitsuka asks what printing number was on the book she has in her hand. Since the printing number changes depending on the book one sees, this question made Juunichou think. She answers "4" since the most current books are that number. It proved incorrect since Takarabe borrowed the book from Kumagawa, who got one of the first books. Juunichou accepts the defeat and passed them from the 2nd trial.
Bouquet Toss To The Future Arc
Ten years later, Juunichou is a librarian at the library of congress.
Superhuman Memory: Juunichou possesses perfect memory. She can remember and recall everything that she has ever experienced, encountered, or learned in her lifetime. She needs only to read, hear, or see something once and she will never forget it. Her mind has unlimited storage capacity, and she is able to immediately recall any information she has stored with perfect clarity. She's able to store everything that she experiences in a photographic memory and retrieve it immediately without the typical human pause for thought. She is able to memorize entire books, down to the exact word used in any part of the book, earning her the title of "Mobile Library" (移動図書館 Idou Toshokan) from the student body.
- Except for her introduction, Juunichou has always begun her dialogue with quotes from popular classical books.