Ritsuko Sakakibara

Ritsuko Sakakibara (榊原 理津子, Sakakibara Ritsuko) is the older sister of Reiko Mikami, the deceased wife of Yōsuke Sakakibara, and the mother of Kōichi Sakakibara, who only appears in the school graduation album and the old Sakakibara family pictures. She went to Yomiyama North Middle School in 1972 and was in the same class as the dead Misaki Yomiyama, 9th Grade Class 3-3.