Kushisake-Onna
From: Japan
One of the most popular and well-known Japanese urban legends is the story of Kushisake-Onna, who lived in rural day Japan. Story goes, because of her cheating on her husband (or just because her husband was jealous of her beauty, the versions vary), her samurai husband severely hurt and disfigured her face. Since she was a noble, she is often said to wear a white kimono (when Japanese people are buried, they wear a white Japanese funeral kimono called a kyoukatabira). However, many yokai (Japanese ghosts, usually evil) women have their hair down. However, women were buried with their hair up. This suggests that these women never received a proper burial. These jokai (female Japanese ghosts) are almost always geishas (women with white painted faces and various makeup), as well.
Now, as a supposed ghost, she haunts places in Japan. She has a mask over her face, hiding her slit mouth, and asks people if she's pretty. Versions vary, but she will usually ask again, taking off the mask, depending on the answer. In many versions, she hunts young males that look like her spouse, and none will be able to escape her. She also supposedly carries a sharp weapon with her, most likely the weapon with which her now-dead husband killed her with. In a few versions, she may hunt just young beautiful Japanese girls because of what happened to her.
Now you've met Kushisake-onna, the slit-mouth sword woman!