^ It's been years that I'm postponing that reading, so the situation remains unchanged. Now, people do tend to refer to her story as an Urban Legend, but setting aside any long comments about the difference between Urban Legends and Creepypastas, Hasshaku-sama's story originates from a "scary stories thread" on 2ch in 2008, hence why I consider it a Creepypasta.
Kuchisake-onna is a pretty old urban legend, and like I said even spawned (at least) 2 movies, so it's actually kinda surprising that you heard of Hasshaku-sama but never of Kuchisake-onna.
Kayako is the main ghost of the Ju-On movies, of which have an american remake called "The Grudge".