Yuki Yoshikawa attends Katagiri Senior High School, Class 3-1, within the same friend circle as Kyouko Hori, Izumi Miyamura, and Tooru Ishikawa. She possesses a slim build, stands around 161 centimeters tall, and has distinctive yellow eyes. Her hair color shifts between olive-green and golden across depictions, typically styled with center-parted bangs and sometimes worn in pigtails. She consistently pairs her school uniform with an oversized, dark gray or coffee-brown cardigan originally belonging to her older sister, Miki Yoshikawa. The cardigan's sleeves are stretched and long enough to cover her hands due to her habit of pulling on them. Like Hori, she wears gym shorts under her skirt. Outwardly cheerful, friendly, and upbeat, Yuki easily creates lively atmospheres and forms friendships, quickly accepting Miyamura despite initial confusion. Academically lazy, she frequently sleeps through classes and relies on Hori's notes and homework. Beneath this happy-go-lucky exterior, she grapples with significant emotional conflict. Yuki habitually conceals her true feelings behind a smile, avoids expressing personal desires, and downplays her emotional state. Stemming from a long habit of not asking for what she wants, she often feels things she likes escape her. Jealousy surfaces, particularly concerning Tooru Ishikawa's interactions with Sakura Kouno, alongside an inferiority complex leading to self-deprecating remarks. Her internal struggles include fear of vulnerability and a pattern of resigning herself to loss. Her background involves a close family with her sister Miki and regular visits to the Ishikawa household for video games. Though academically unmotivated, she possesses practical sewing skills, often carrying a kit to mend clothes for classmates or teachers. Her baking attempts consistently fail, yielding poorly received creations like malodorous cakes or cookies containing foreign objects, though rare successes happen. She is notably accident-prone, frequently tripping, bumping into walls, or injuring herself through inattentiveness. Yuki's romantic focus centers on Tooru Ishikawa. Following Hori and Miyamura's relationship, she and Ishikawa grow closer, though mutual misunderstandings about feelings persist. When Akane Yanagi confesses to her, Yuki fabricates a relationship with Ishikawa to reject him, leading to a public pretense of dating. This arrangement strains her emotionally as Sakura Kouno develops genuine feelings for Ishikawa. Yuki's unexpressed love culminates in depression when Sakura confesses to Ishikawa, believing he will reciprocate. However, Ishikawa rejects Sakura and expresses his preference to stay with Yuki. Their relationship evolves ambiguously, with interactions hinting at mutual commitment alongside unresolved uncertainty, highlighting Yuki's gradual, though incomplete, progression toward confronting her feelings instead of retreating. Her birthday is July 22, making her zodiac sign Cancer. Nicknames include "plebe" reflecting her simple tastes; she dislikes expensive foods, favoring common dishes. She appears in Ishikawa's dreams as a mouse named "Yukicchu." Her name combines "reason" (由) and "chronicle" (紀) for Yuki, and "lucky" (吉) and "river" (川) for Yoshikawa.