Yu (由宇 Yū) is Arata Wataya's neighbour in Fukui.
Yu is of average height, with short black hair with bangs and brown eyes. She wears her navy blue sailor fuku-style school uniform. During cold weather she adds a pink scarf and a beige cardigan.
Yu and Arata are schoolmates. He tried to convince Yu to start a karuta club with him, but she said no.
- She used to play karuta back in elementary school.