Appears in the story "The Case of Hidemi and Nanae", which takes place in 1986. Taizou is Hidemi's childhood friend. He worries about her but is pushed away every time he expresses concern or tries to give her advice. He doesn't know that she likes him, and appears to be interested in a girl from another school. After Hidemi confesses to him, she finds out that Taizou loves her too and that the girl she saw him with is his younger sister, Taeko. Many years later, Shinobu's name is revealed to be "Ryuugasaki", since Hidemi and Taizou got married and had her as a daughter.