Should you find yourself on the streets of Tokyo at night, be wary of any young woman wearing a surgical mask who wishes to speak with you - and this might be tougher than you think as surgical masks are commonly worn by the sick and those wishing to avoid sickness in Japan. There is a ghoulish spectre who takes advantage of the common use of masks for her own vicious ends, and she is known as Kuchisake-onna, the slit-mouthed woman.
Appearing as a beautiful young woman, dressed stylishly and wearing the surgical mask, she will approach and ask "do you think I'm pretty?" If you answer yes, she will remove the mask, revealing that her mouth has been slashed from ear-to-ear, and ask "do you think I'm pretty, now?" Those who answer "no" will be killed with the knife or shears that she carries, those who answer "yes" will be followed home, where they will be killed and their mouths cut to resemble Kuchisake-onna's.
There are many stories describing the origins of this malicious spirit, but the most common one is that she was the wife of a Samurai. She was a beautiful woman, and she may have been cheating, or the samurai may simply have been pathologically jealous and convinced that she would stray. Regardless, one day, he took a blade to her mouth, slicing through both cheeks, while screaming "who will think you're beautiful now?" Whether he killed his wife then and there, she died of her injuries, or she lived but harbored malice for the wrong done to her is unknown.
What is known is that she has been said to appear throughout Japan, and in specific places in nearly every neighborhood of Tokyo.
Commentary: This is a classic urban legend from Japan. Kuchisake-onna has been known since at least the 1970s, and may date to even earlier (at least one source claims that it is derived from a legend that may be as much as 1,200 years old, though it is also possible that the legend and the urban legend were linked together post-hoc). Rumor holds that there are coroner's records from the late 70s that describe a woman who had been chasing small children was either killed or injured when hit by a car, and that her injury involved the ripping of the cheeks, possibly spawning a Kuchisake-onna scare in 1979.
In true urban legend style, there are many variations on the story. Although usually told as a ghost story - the woman is the wife of a medeival Samurai - there are variations in which she is a recent victim of domestic violence, or the victim of an incompetent plastic surgeon, and therefore may be a ghost or may simply by a person who has suffered a psychotic break due to trauma. In some variations of her story, the victims are not killed, but simply have their mouths slit. Also, in some versions of the story, answering "yes" a second time will result not in death or injury, but in Kuchisake-onna giving the potential victim a valuable but blood-covered ruby.
It's worth noting that the Japanese versions of the phrases "Am I pretty?" and "Am I to cut?" sound very similar. This particular spirit isn't just evil, she's evil enough to crack bad puns.
Kuchisake-onna also moves with the times. Some variations on the story hold that she can move up to 100 meters in 3 seconds, faster than an automobile (potentially preventing escape by vehicle). Others hold that she now drives a red sports car, thus eliminating the need for her to run quickly.
Also, over time, ways to escape Kuchisake-onna have entered the legend. In some versions, answering "yes" a second time allows escape, in others, telling her that she is "so-so" or "of average appearance" confuses her and escape can be made while she tries to figure out what to do next. A particularly funny escape plan holds that saying the word "brillcream" three times will help you escape. In one of my favorite versions of the story, throwing a piece of Pocky, candy, or some fruit at her or on the ground will force her to try to dodge it or pick it up, allowing escape.
What's interesting to me about the escape methods is that they all seem to follow a pattern seen for vicious monsters in folklore around the world - provide them with a task they must complete (picking up the Pocky) or confuse them (always in some formulaic way - you'd think that these creatures would eventually work out a standard course of action) and you can escape. It just goes to show, whether urban legends or ancient myths, folklore seems to follow some basic rules.
It's worth noting that there are two films based on the Kuchisake-onna legend. Fans of Japanese horror films may want to look into them.
Oh, Youtube searches, is there anything that you can't do?
Sources: Japan Times, Hometown Tales Podcast, Scary for kids, Blog, Wikipedia, Internet