Chiya's grandmother founded and operated the family café Ama Usa An, establishing it as a historical rival to Rabbit House, run by Chino Kafū's grandfather. This rivalry originated from professional competition, though she personally held no serious animosity and did not actively fuel the competitive dynamic.

She displayed a stern, traditional approach to café management. During a work exchange, she trained Chino at Ama Usa An, adopting a strict demeanor by threatening relentless work and criticizing her as "greedy" or "presumptuous." Despite this harsh exterior, she demonstrated underlying kindness by preparing monaka and youkan snacks for Chino and offering tea, indicating a mentorship style balancing discipline with care.

Her relationship with Chino's grandfather involved both rivalry and collaboration. They jointly created a "coffee anmitsu" dessert for a promotional event, which became highly popular. She harbored lighthearted resentment when this item overshadowed her other creations, reacting with playful pouting, reflecting a complex but ultimately respectful professional history.

She entrusted daily operations of Ama Usa An to her granddaughter Chiya, supporting her innovative approach to renaming sweets with elaborate titles. Though initially resistant to reviving historical items like the coffee anmitsu, she accepted Chiya's decision to preserve that legacy of collaboration as inspiration for future partnerships between the cafés.

Her personality included teasing humor, seen when she adjusted a kimono originally meant for Syaro Kirima so Chino could wear it during training. This act subtly acknowledged shifting relationships between the younger generations while maintaining her characteristic sharpness in dialogue.