Ritsuko Sakakibara

Ritsuko Sakakibara is Kouichi's deceased mother and Yousuke's wife. She only appears in the school graduation album. She went to Yomiyama North Middle School in 1972 and was in the same class with the dead Misaki, 9th Grade Class 3.

Personality
Her personality is unknown, since she died when Kouichi was still a baby.

Appearance
She has brown hair, as well as brown eyes in the anime, and has brown hair and black eyes in manga. In her middle school days, she wears a ponytail in the anime. In the manga, her hair is shoulder length and her hair is worn down. Her appearance in her adult days is never shown.

Plot
It is unknown whether she died while giving birth to Kouichi, or if she died shortly after his birth. In chapter 10, it is hinted that her mother's death was most likely caused by the Class 3-3 curse, since her sister, Reiko, was in that class. After her death, his father (Kouichi's grandfather), is always seen sitting in front of her altar, probably still depressed about her death. In Episode 5, when Kouichi was looking at his mother's class picture, the librarian, Tatsuji Chibiki came to him and asked about his mother. Tatsuji is shown to know about his mother, since he was the homeroom teacher of class 3-3 in 1972.

Fan Specululation
Reiko Mikami is really alive and Ritsuko Mikami is Mikami-sensei (dead one) as Reiko doesn't ask who the Vice-Teacher is (If she really isn't Mikami-sensei) and Sakakibara didn't know how her mother would look like as an adult, plus the fact that people are brainwashed.

Trivia

 * Her first name, Ritsuko, means "child of the law".
 * It is affirmated the fact that Ritsuko and her sister, Reiko looks a lot alike.