Hanako-san of the toilet

A ghost said to live in a girls' toilet stall in Japanese schools, called out by knocking and saying her name. Japanese Wikipedia traces the story to about 1950; it spread among children nationwide from about the 1980s.

Atlas Obscura says Hanako's origin varies with each teller, but she is usually a girl who died around the Second World War and now haunts school toilets. She is pictured in an old-fashioned red dress with a bob. To call her, you go to the girls' toilet on the third floor, knock three times on the third stall and ask if she is there. Depending on the region, she answers yes or a hand appears.

Writer Yamaguchi Bintarō, in AERA dot, says Hanako appears only when people summon her with a ritual. The ritual differs from one primary school to the next, he writes, but the core is the same: knock three times on the third stall from the back, or the front, of the girls' toilet on a given floor and call her name.

Japanese Wikipedia traces her to a rumour called the Third Hanako, told from around 1950. It says she became a rumour among children across Japan from about the 1980s and appeared in films, manga and anime during the second occult boom of the 1990s. English Wikipedia cites author and folklorist Matthew Meyer dating the legend to the 1950s. It also cites Michael Dylan Foster, who wrote The Book of Yōkai. Foster calls Hanako-san an urban legend known in schools across Japan that entered popular culture through films from the 1990s.

Eiga.com lists a 2013 film, Toire no Hanako-san Shin Gekijōban, and notes the story had already been filmed many times. Ueno Yūka stars. In the film a high school girl moves with her mother from Tokyo to her grandmother's country town, where a girl she befriends is bullied and locked in a school toilet.