Shin-chan's teacher. Age 24. She is always in bitter rivalry with Ume Matsuzaka. However she unhesitatingly supports Matsuzaka in certain critical situations. "Yoshinaga" is her maiden name. Her last name changed to "Ishizaka" after getting married to Junichi Ishizaka on July 7, 2000. Before him, she didn't have much luck with her boyfriends, often commiserating with Matsuzaka about their lack of love life.