Okudaira Sakiko is the mother of Akira and Shinobu.

She is long-time friends with Fumi's mother and the Manjoume family. Her relationship with Fumi's mother is rekindled when they move back, and she is rather excited to have her friend again.

She has a very close relationship with both her children as she is seen joking around with them and having conversations with them regularly. However, she is also rather stern and blunt. Whenever Akira and Shinobu fight, one glare from her is enough to quieten them. She often has to tell Shinobu to get a life and leave Akira alone.

Akiko was considered to be the "outlaw" of the family by Keiko, her very disapproving relative in Yokohama, whom she makes Akira go visit.