Yoriko has short brown hair and brown eyes.
Yoriko is a concerned mother, such as when she calls Chiaki and tries to get him to eat more vegetables. She can be both pleasant and fierce with her children, welcoming Chiaki home but slipping immediately into intimidation to demand he not run off too quickly.
She is very flattering to Yoshiyuki Hatori, calling him handsome and congratulating him on his position as second-editor-in-chief. She is more critical of her son's accomplishments.
Although Yoriko is eager for both her children and Hatori get married and have families, she seems oblivious to their romantic interests, seemingly completely unaware that Chiaki and Hatori are in a relationship together and that Chinatsu has a crush on Hatori.
A year after Chiaki and Hatori begin dating, Yoriko calls her son. She gives him some grief about eating vegetables and insists that he comes over once in a while to visit. After getting off the phone, Chiaki talks to Hatori, and they decide to visit Chiaki's family together since Hatori is also going to his parents' to feed their fish while they're away, so Chiaki can stay with Hatori at his parents' place.
They visit Yoriko and Chinatsu that day, and she comments that Hatori has become even more handsome since she's last seen him. She offers them watermelon and the boys try to make their escape but she firmly tells them not to run away. They accept the watermelon and talk.
Yoriko is flattering and encouraging to Hatori's work, but critical of Chiaki's. She's concerned that he's wasting his time and says he should stop and "go find a nice girl." She also asks Hatori about his relationships, but like Chiaki, he claims he's too busy. Yoriko suggests he date Chinatsu, which startles both her children and Chinatsu accuses her of making this awkward for Hatori. She then asks Chinatsu if she's seeing anyone, and Chinatsu tells her it's not her business. Hatori politely says that Chinatsu is lovely and deserves someone better than him, which causes Chinatsu to quickly leave the room, upset. Chiaki is also upset and borrows the keys to Hatori's parents' place and leaves. Yoriko calls after him to take the vegetables, but he doesn't listen, leaving only Hatori and Yoriko in the room.
Hatori later takes the vegetables and leaves as well.