Hiyori Shiina

Biodata

Feature	Information
Name	Hiyori Shiina
Alias(es)	Shiina; Shiina-san
Original Name	椎名日和
Gender	Female
Affiliation	Class C; Special Project Research Group
Occupation/Role	Student at Tokyo Metropolitan Advanced Nurturing High School
First Appearance	Chapter 5

Background / History

Hiyori is a quiet Class C student who initially struggles to fit into the class's hostile atmosphere under Ryuen Kakeru. She often retreats to the library, which she considers a peaceful refuge from Class C's chaos. She is an avid reader with particular interest in difficult and obscure material. 5 43

She first meets Ayanokoji Yuefeng in the library while attempting to retrieve Modern Art Philosophy from a high shelf by standing on an unstable chair. When she falls, Yuefeng catches her and takes the impact against a bookshelf himself. Flustered but grateful, she invites him for tea afterward; their conversation over books establishes their connection. 5

Though Hiyori initially comes across as shy and easily embarrassed, she possesses substantial academic ability. She sees through Yuefeng's attempt to conceal his advanced studies and privately directs him to specific chapters and appendices relevant to his exam preparation. She has also independently researched the exam, hoping that more students from Class C will pass and improve the class atmosphere. 9 10

Appearance

Hiyori is a petite, slender girl with a quiet, delicate appearance. Her reserved body language often reflects her shyness, particularly when speaking to Yuefeng. 5 18

• Light brown eyes. 5
• Long dark brown hair, worn loose over her shoulders outside school. 43
• Fine bangs that partly obscure her brow and eyes while in uniform. 6
• Often carries books or holds them against her chest. 5 9
• Wore a simple white one-piece swimsuit at the indoor pool. 42
• Wore a light blue dress while meeting Yuefeng in the hydrangea garden during vacation. 43

Personality

Hiyori is gentle, introverted, and soft-spoken. She is easily flustered in personal interactions, especially around Yuefeng, but becomes noticeably more articulate and confident when discussing books, logic, or academic subjects. 5 15 29

She is kind and conscientious despite Class C's harsh environment. She gives Yuefeng ointment after noticing his injury, provides him with study resources without exposing his hidden ability, and intervenes when Ishizaki coerces Onodera into cheating. 6 9 10

Hiyori is perceptive beneath her timid exterior. She recognizes Yuefeng's concealed academic effort, notices fear in the students she interviews, senses Ishizaki's suspicious activity, and asks Ibuki Mio to watch over Yuefeng when she believes he may be in danger. 9 31 36

She also has vulnerabilities. Losing the Cherry Blossom Crystal pendant left by her mother devastates her, and she is deeply affected by rumors claiming Yuefeng was injured while protecting her. Nevertheless, she recovers with support and becomes more determined to contribute to Class C. 18 22 44

Abilities & Skills

Logical Analysis

Hiyori has strong aptitude in logic, cognitive science, and social decision-making. Her academic performance earns her selection for the Special Project Research Group alongside students regarded as representatives of their classes. 26 27

• Identifies hidden assumptions and logical fallacies in group discussions. 33
• Provides theoretical grounding through logical and cognitive perspectives. 28 33
• Helps examine hidden traps and potential scoring opportunities in the Uninhabited Island Special Exam rules. 47
• Is recognized by Katsuragi Kohei and Horikita Suzune, who listen seriously to her supplementary analysis. 36

Academic Research

Hiyori is a dedicated reader and researcher whose knowledge extends beyond standard first-year coursework. 5 9

• Recommends precise sources for Yuefeng's economic-model research, including chapters nineteen through twenty-two of one text and an appendix in another. 9
• Supplies Yuefeng with printed coursework and offers to lend him papers related to game theory. 15 16
• Participates in quantitative analysis for the research group's study of the school's S Points system. 29
• Conducts interviews and takes notes during the group's research process. 36

Observation

Hiyori quietly observes people and situations despite appearing withdrawn. 9 10

• Notices that Yuefeng's library notes and reading exceed the expected exam scope. 9
• Detects anxiety and evasiveness in Airi Sakura's interview responses. 36
• Warns Yuefeng of rumors that Ishizaki is arranging private point-based transactions and resolving “trouble” for others. 36
• Correctly anticipates that Ishizaki may target Yuefeng, leading her to ask Ibuki to watch over him. 31

Basic Survival Preparation

Before the Uninhabited Island Special Exam, Hiyori studies the rules with Yuefeng and receives basic physical and wilderness-survival training from Ibuki Mio. 46 47

• Trains in danger recognition and basic self-protection under Ibuki's guidance. 46
• Uses her analysis skills to help Yuefeng interpret the exam's rules. 47
• Acknowledges her limited preparation but resolves not to hold the class back. 48

Equipment / Items

• Cherry Blossom Crystal pendant — A cherished pendant left by her mother. It is lost after Ishizaki's group bumps into her near the gymnasium path, then recovered by Yuefeng beneath fallen leaves. 18 19
• Embroidered cloth pouch — Used to hold the pendant; she clutches it when distressed over its loss and later amid the rumors surrounding Yuefeng. 18 22
• Books and research materials — Frequently carries books and supplies academic sources, coursework, and research papers. 5 9 15 16

Relationships

• Ayanokoji Yuefeng — Classmate, study partner, and increasingly close confidant. He saves her in the library, finds her pendant, comforts her over rumors, and repeatedly affirms her ability. Hiyori helps him study, shares the library's Old Book Section with him, and shows concern for his safety. Their interactions carry mutual shyness and implied attraction. 5 9 19 23 31 42 43
• Ibuki Mio — Protective friend and self-defense instructor. Ibuki attempts to comfort Hiyori after the pendant is lost, helps search for it, watches over Yuefeng at Hiyori's request, and trains Hiyori before the island exam. 18 19 31 46
• Ishizaki Daichi — An intimidating Class C classmate whose actions repeatedly trouble Hiyori. He threatens Yuefeng to stay away from her, coerces Onodera before Hiyori stops him using school rules, and may have caused her pendant to fall when his group bumped into her. 6 10 19
• Ryuen Kakeru — Class C's dominant figure, whose oppressive influence contributes to Hiyori's initial discomfort within the class. 5 43
• Airi Sakura — Research interviewee. Hiyori recognizes Airi's fear and attempts to make the interview less intimidating through gentle questions. 36
• Special Project Research Group members — Works with Sakayanagi Arisu, Katsuragi Kohei, Ichinose Honami, Horikita Suzune, Hirata Yosuke, and Yuefeng. Her logical contributions become increasingly respected within the group. 26 27 36

Story Role / Major Arcs

Library Encounter and Special Exam

Hiyori enters the story when Yuefeng rescues her from a fall in the library. She treats him to tea, warns him to be wary of Class C's environment, and bonds with him through their mutual love of reading. 5

She later supports Yuefeng's preparation for the special exam by identifying his hidden ability, supplying targeted materials, and subtly revealing a useful hint during the exam itself. 9 10 12

Pendant Search and Sports Festival Rumors

Hiyori is devastated when she loses the pendant left by her mother. Yuefeng and Ibuki search with her, and Yuefeng ultimately finds it along the path where Ishizaki's group had bumped into her. 18 19

After Yuefeng is injured during the Sports Festival, rumors spread that he was hurt protecting Hiyori from Ishizaki. Hiyori blames herself and cries alone, but Yuefeng reassures her that she is not responsible. She later shares her secret spot in the library's Old Book Section with him. 22 23

Special Project Research Group

Hiyori is chosen as one of Class C's representatives for the Special Project Research Group due to her academic performance and logic-class ability. Her research interest is logic, cognitive science, and their application to social decision-making. 26 27

As the project progresses, she becomes increasingly confident in debate, provides rigorous logical analysis, and works directly with Yuefeng on interviews and quantitative research concerning the S Points system. 29 33 36

Summer Vacation and Uninhabited Island Exam

Hiyori invites Yuefeng to join Class C's summer pool trip. Their quiet time swimming together makes their mutual feelings more apparent, though neither explicitly defines them. 41 42

On the final day of vacation, she confides that she initially felt alone at the school and found refuge in the library. She tells Yuefeng that meeting him and later joining the research group made her feel less isolated. 43

With the Uninhabited Island Special Exam approaching, Hiyori resolves to work harder for Class C and not disappoint Yuefeng's trust. She studies the rules with him, accepts Ibuki's survival training, and commits to doing her best without holding the others back. 44 46 48

Notable Quotes

“I... am quite interested in logic, cognitive science, and their applications in social decision-making.” 27

“Later... I met Yuefeng in the library, and then... we were in the group together... It felt... like I wasn't so alone anymore.” 43

“I will do my best. I won't hold everyone back.” 48

Trivia

• Hiyori's first conversation with Yuefeng becomes more animated when they discuss books. 5
• She calls the library a wonderful place because of its quiet atmosphere. 5
• Her selection for the Special Project Research Group makes her less isolated in Class C and draws admiration from ordinary classmates. 29
• Despite her timidity, she is willing to confront misconduct by citing school rules when Onodera is pressured to cheat. 10