Shizuko Yasuda, the third ex-wife of Genichirou Miyanomori and mother of Shigeru Miyanomori, rose from her youth as the number one geisha in Osaka's Kansai region. Renowned for her professionalism and dedication, she later became proprietress of the luxurious traditional Japanese restaurant Yasuda, maintaining significant financial and political connections despite her career transition.

Her marriage to Genichirou stemmed from his intervention in resolving a "nasty trouble" she faced, though his motives weren't purely altruistic. He acknowledged her status as Kansai's top geisha and had interest in the "circumstances" of her background, particularly concerning how their son Shigeru would navigate societal stigma as the child of a geisha. The marriage produced Shigeru but ultimately ended in divorce.

Physically, Shizuko possesses long black hair, typically secured in a tight bun with bangs swept to the left, and black eyes. She frequently wears a dark red-purple kimono patterned with small golden flowers and light pink lipstick, reflecting her refined aesthetic.

Personality-wise, Shizuko exhibits kindness, particularly towards Haru Asagi and her son Shigeru, coupled with a strong will when defending herself or her family's interests. She rejects formalities and embraces hobbies like driving, which she learned for enjoyment and mood changes, though her driving skills unsettle passengers. A pragmatic outlook defines her management of the Yasuda restaurant and navigation of complex social dynamics.

Her relationship with Shigeru is central. She remains supportive despite his identity struggles and resentment towards Genichirou, humorously gifting him repetitive presents like straw hats on multiple birthdays. Her interactions with the Miyanomori family blend maternal protectiveness with pragmatic distance, especially visible during Shigeru's confrontations with Genichirou over family legacy and personal grievances.