Kage onna are the shadows of women projected onto windows and doors when there is no one around to cast them. They usually take the form of young ladies, though occasionally they appear as old crones with bells hanging from their necks. They appear late at night, when the moon is bright. The paper sliding doors and windows of traditional Japanese homes are particularly good at catching kage onna shadows in the moonlight.
Kage onna make no sound, nor do they interact with the house or its inhabitants. Other than projecting an eerie atmosphere, they are not known to cause any harm. In any case, the image of a person who should not be there is enough to startle the bravest person. If the door or window is opened to see who or what created the shadow, there will be nothing waiting in the dark. However, tradition says that a house where a kage onna is seen is likely haunted or will soon be haunted by other yokai as well.
The moonlight frequently plays tricks on the eyes, causing people to see things in the darkness that aren’t really there. The bright moon casts eerie shadows on the ground and walls that don’t seem like they should fit. Most of the time, this can be attributed to an overactive mind piecing together ghost stories and wandering thoughts, or constructing some horrible figment of the imagination. Sometimes, however, a shadow is more than a shadow; sometimes it is a kage onna.