Traditionally, if someone holds a sufficient grudge against another person, it is believed that a part or the whole of their soul can temporarily leave their body and appear before the target of their hate in order to curse or otherwise harm them, similar to an evil eye. However, this temporary separation would result in sickness."If the separation became permanent, the person who held the grudge would die."
The Ikiryo are said to be able "to possess another living person without the originator even being aware of it." The spirits are not "tied to whomever they possess," however, and "may freely move about bodies."
^Clarke, Peter Bernard (2000), Japanese new religions: in global perspective, Volume 1999 (annotated ed.), Routledge, p. 247, ISBN978-0-7007-1185-7
^Anderson, Richard W. (April 1995). "Vengeful Ancestors and Animal Spirits: Personal Narratives of the Supernatural in a Japanese New Religion". Western Folklore (Western States Folklore Society) 54 (2): 113. JSTOR1500400.|accessdate= requires |url= (help)
^Fairchild, William P. (1962). "Shamanism in Japan". Folklore Studies (Nanzan University) 21: 33. JSTOR1177349.|accessdate= requires |url= (help)
^Yunesuko Higashi Ajia Bunka Kenkyū Sentā (Tokyo, Japan) (1972). East Asian cultural studies. Centre for East Asian Cultural Studies. pp. 48–53. Retrieved 20 September 2011.
^Ellis S. Krauss; Thomas P. Rohlen; Patricia G. Steinhoff; Joint Committee on Japanese Studies, Social Science Research Council (U.S.) (1984). Conflict in Japan. University of Hawaii Press. pp. 88–. ISBN978-0-8248-0867-9. Retrieved 20 September 2011.
^"Ikiryoh". The Element Encyclopedia of the Psychic World1. Harper Element. 2006. p. 317.|accessdate= requires |url= (help)