Yasuko Nonomura is the mother of Ami and Hiroshi Nonomura, forming the core of their family unit within a shared household. She maintains the household's domestic rhythm, notably preparing shared family breakfasts each morning. Yasuko holds a job outside the home, commuting to work by car. Her work schedule requires her daytime absence from the house. She is shown fulfilling typical parental responsibilities, such as getting ready for her own workday while her children prepare for their activities. Her presence defines the foundational family structure central to the narrative involving her children.