A household spirit resembling a child of either gender from about three to twelve years of age. The name zashiki-warashi comes from the interior of Iwate Prefecture, but similar legends are found all over Japan. It is often said that when this being dwells in a house, its family will be prosperous, but when it leaves, the house will fall into ruin, and also that the zashiki-warashi is never seen, save for just as it is about to leave. Its presence however, is often marked by the mischief it does to sleeping people, such as moving pillows about and pulling on bedding.

There are different kinds of zashiki-warashi which vary in pleasantness, with the chōpirako variety said to be pretty and white in color, and the notabariko or usu-tsuki-warashi sort said to crawl out from beneath the dirt floor and creep about, making noises like pounding a mill-stone and causing unpleasant feelings. The latter sort seems to be connected to old infanticidal customs called mabiki (thinning-out), which often ended in burying unwanted infants somewhere in the house, such as under a dirt floor or a mill-stone.¹

Citations:
1. Murakami 2000 p. 171, Murakami 2005 pp 153-154.