Mitsuko Yamaoka is a supporting character in the anime and manga series Mister Ajikko. She is a childhood friend and classmate of the protagonist, Youichi Ajiyoshi, and also the older sister of Shigeru Yamaoka. Mitsuko works part-time as a waitress at Hinode Eatery, the restaurant run by Youichi and his mother. She helps out both as a favor to Youichi's mother and as a way to stay close to Youichi, though he remains completely unaware of her romantic feelings for him. Mitsuko harbors a hidden crush on Youichi that she tries to keep secret, but her younger brother Shigeru frequently teases her about it. In terms of personality, she is friendly and diligent, but she can be sharp-tongued when necessary, often scolding Shigeru for taking advantage of people's hospitality, particularly when he begs for free food. She is not skilled at cooking herself; in fact, her attempts at cooking are described as terrible, and her younger brother refuses to taste her creations. Despite this, she has some knowledge of food and cooking, which allows her to follow along with culinary discussions. Her primary role in the story is as a supportive friend and helper at the restaurant. She and Shigeru frequently act as taste-testers for Youichi's new dishes, providing feedback and encouragement. Mitsuko’s motivation is rooted in her affection for Youichi and her desire to be close to him, as well as her loyalty to the Ajiyoshi family. She does not undergo significant character development over the course of the series; her unrequited feelings remain unresolved, and in the sequel series Mister Ajikko II, Youichi marries a different woman, Yae, leaving Mitsuko's role as that of a long-time friend and supporter. Her notable abilities are limited to her waitressing duties and her willingness to assist in any way she can, though she possesses no exceptional culinary talent or special powers. Overall, Mitsuko Yamaoka serves as a warm, everyday presence in Youichi's life, representing the ordinary, supportive side of the community around Hinode Eatery.