|Status||Alive / Trapped|
|Voice Actor||Masami Mizuno|
Yoriko has a huge crush on her teacher, and she is quite abrasive and hysterical at times. However, she has a good heart, and has a surprising reserve of courage when called upon to fight.
The night before the first day, at the 23rd hour, Yoriko was sleeping in the passenger seat of Takeuchi's car. Takeuchi sneaked out of the car without her noticing. An hour later, she left the car after realizing that Takeuchi was missing. While searching and calling out for him, a siren rang before an earthquake caused her to lose consciousness for two hours.
At the 12th hour, unable to bear the dryness of her throat, Yoriko tried to drink from a spring on shrine grounds, but this angered Takeuchi, resulting in her being left behind. At some point, Yoriko searches for her student ID, having previously lost it. Yoriko was discovered by Shibito, and startled and in a panic, she attempted to flee when she was saved by Akira Shimura. Yoriko then bore witness to the umi-gaeri at the edge of village. Shimura, whom had been accompanying her, committed suicide. Despite being shocked, after a few hours, Yoriko finally reunited with Takeuchi. She also displayed a self-sacrificial mentality when she used herself as a decoy to help out Takeuchi.
Day 2 on the 16th hour, Yoriko and Kyoya were taken to the hospital by Miyata. Kyoya's blood enters Yoriko, and she too inherits immunity to transforming into a Shibito. She infiltrated the Shibito Nest with Kyoya, and through her quick thinking, secured a path. By midnight, they arrived at the Mirror Pool, present at the descent of Datatsushi. They were attacked by Datatsushi when Takeuchi saved them.
Later, Yoriko found Takeuchi inside the nest, but lost sight of him in a muddy cascade.
A few days later, she broke into the Takeuchi house to discover her teacher in an entranced state, and after beating his Failed-Shibito parents with a baseball bat, she pulled him away.
- Yoriko is a student at Josei University, her student ID number being 310705. She is majoring in Folklore Cultural in the Anthropology Department of the School of Humanities.
- Yoriko attempted to write and send a postcard to her parents, revealing that she departed on her journey in the middle of the night to assist one of her "professors with his research". Her mother and father are named Hideo (秀男?) and Masako (正子?) respectively, and they live in Shinagawa.