TV-Series
Description
Sachiko Ogasawara, eldest daughter of the wealthy Ogasawara family and often called a "Japanese Princess," attends prestigious Lillian Girls' Academy. She rises within the Yamayuri Council student leadership, from Rosa Chinensis en bouton to Rosa Chinensis. Her life includes an arranged engagement to her cousin, Suguru Kashiwagi, intended for the family business. This caused her distress as she developed feelings for him, though he did not reciprocate due to his homosexuality. The engagement dissolved after Sachiko confronted her parents about its basis in a forgotten childhood promise. Witnessing her father and grandfather maintain mistresses fostered her misandry and disdain for men, leading to an aversion to male interaction, like refusing to dance with Suguru or discomfort with the all-male Hanadera Student Council.

Sachiko combines elegant aloofness with a volatile side, often perceived as cold and distant. Forming a soeur relationship with Yumi Fukuzawa reveals a more carefree and protective nature. She shields Yumi from social pressures during a summer vacation confrontation. Sachiko also struggles with jealousy, particularly over Yumi's closeness to Sei Satō, reacting by scolding them or making excuses to leave. Her flaws include stubbornness, difficulty expressing vulnerability, and concealing personal struggles, causing relationship misunderstandings.

Her character development centers on her bond with Yumi, whom she impulsively chooses as petite soeur after straightening Yumi's neckerchief, partly to avoid playing Cinderella opposite a male lead. Yumi's initial rejection forced Sachiko to reflect. Their trust deepened when Sachiko confided about her engagement during an emotional greenhouse breakdown. Yumi later helps Sachiko navigate everyday experiences unfamiliar due to her sheltered upbringing, like shopping for jeans or dining at fast-food restaurants. Sachiko overcomes acrophobia to climb down a two-story ladder to reach Yumi during a school festival and gradually moderates her misandry through necessary male interactions.

Key challenges include her grandmother's death triggering a depressive withdrawal from school. Yumi, brought by former grande soeur Yōko Mizuno, helps her through this grief, leading to reconciliation. Later, strain arises with Yumi when cousin Touko Matsudaira arrives, sparking jealousy, though Sachiko remains committed to supporting Yumi. As Rosa Chinensis, Sachiko mentors Yumi to seek her own petite soeur, reflecting her evolving leadership and concern for Yumi's Yamayuri Council legacy.

Sachiko deeply cares for peer Rei Hasekura, intervening in Rei's conflicts with petite soeur Yoshino and offering emotional support during Rei's crises. Her loyalty extends to grande soeur Yōko, honoring her by fulfilling a wish to open the Rose Mansion for a Valentine's Day event. Despite her reserved exterior, Sachiko exhibits moments of warmth and vulnerability, like crying in Yumi's lap or holding her hands for comfort, showing her gradual emotional openness.