Chinatsu Hiyama is a central character who becomes the primary dance partner of the protagonist. She is a high school classmate of Tatara Fujita, and her introduction marks a significant shift in the story's focus. Initially, she presents a contradictory front, publicly mocking ballroom dancing as uninteresting while privately being a devoted fan of the professional dancer Chizuru Hongo. This behavior is not merely duplicitous but stems from a complicated personal history with the sport. Chinatsu began dancing at a young age and possesses considerable talent and experience. However, her journey has been marked by difficulty in finding a suitable partner.

Chinatsu’s personality is fiery, strong-willed, and fiercely independent. She is blunt and not afraid to speak her mind, which often leads to conflict. Her time away from dancing was born from frustration; after a series of failed partnerships, she attempted to leave the dance world behind to live a normal life. Her re-entry into the world of competitive dance is reluctant. She is persuaded to partner with Tatara, partly through the machinations of their mentors and partly due to her own pride being challenged by a former partner. Initially, they are a deeply incompatible pair. Tatara struggles to assert himself as a leader, feeling too considerate of his partner, while Chinatsu is accustomed to taking control and resents being led by someone she perceives as weaker. She is used to leading, a skill she developed due to a shortage of male dancers, often taking the male role in female-female practice pairs.

This unique background is her most notable ability as a dancer. Chinatsu is an exceptionally skilled leader, capable of guiding a partner with confidence and precision. Conversely, she has very little experience following, which becomes a significant hurdle in her partnership with Tatara. Her stubbornness as a follower is so pronounced that other characters compare her to a wild horse. Her motivations are rooted in a desire for a true, equal partnership. She refuses to be a passive follower and demands a partner who can prove himself to be on her level, challenging the traditional gender roles of ballroom dance. Despite her abrasive exterior, her deep-seated passion for dance remains, as does a fear of abandonment and partnership failure, causing her to react defensively when conflicts arise.

Throughout her time as Tatara’s partner, Chinatsu undergoes significant development. Her key relationships drive this growth, particularly with Tatara, whose sincerity and dedication force her to confront her own fears and pride. Her dynamic with her former middle school partner, Akira Koumoto, is also pivotal, as it is a rivalry charged with past betrayals and challenges that solidify her commitment to competing again. Her journey is about learning to compromise, building trust, and finding a new form of expression that is neither purely leading nor following, but a mutual creation.