The Baku and the Three Realms

In 9th century Chinese text the Baku is not yet an eater of bad dreams but I think you can kind of see how you would get there so its skin or its image offers general protection from sickness. People with chronic headaches can protect their heads by using a screen with an image of the Baku when they go to sleep. By the Edo period in the beginning of the 17th century the Baku had come to be seen in Japan as an eater of nightmares protecting the weak and this usually worked by placing a picture of the Bakus near the pillowor sometimes people just had a Baku-shaped pillow.