Translation: mirror beyond the clouds
Appearance: Ungaikyō is a haunted mirror which shows demons and monsters reflected in its surface. The spirit which haunts this mirror, as well as the countless spirits which have been reflected in it over the years, can manipulate the reflection and cause it to appear as anything they like. People who gaze into an ungaikyō might see a transformed, monstrous version of themselves looking back.
Interactions: An ungaikyō can be used by humans to trap spirits. On the 15th night of the 8th month in the old lunar calendar, water is poured into a crystal dish to reflect the light of the full moon. (In the old days this was a popular way of admiring the reflection of the night sky.) If that water is used to paint the image of a yōkai onto a mirror, that spirit will then inhabit the mirror.
Origin: Ungaikyō appears in Toriyama Sekien’s book of tsukumogami Hyakki tsurezure bukuro. Sekien based this yōkai on a mirror from an old Chinese myth. That mirror was called shōmakyō (“demon revealing mirror”). It had the ability to expose the true forms of demons masquerading as humans when they were reflected in the mirror. Shōmakyō was used by King Zhou of the Shang dynasty to reveal that his beloved consort Daji was actually a wicked nine-tailed kitsune, intent on runing his kingdom through her evil depravities. Her true form revealed, she fled the country (setting into action a chain of events that would see her eventually wind up in Japan as Tamamo no Mae). Shōmakyō was used time and time again to reveal the true nature of disguised spirits. Sekien postulated that such a mirror might pick up a little of the strangeness of each yōkai and demon it reflected, eventually becoming one itself. Perhaps the countless spirits that is has reflected over the years have slowly gained the ability to manipulate its reflections.
More recently, ungaikyō has been described simply as a mirror which has transformed into a conscious being. Upon reaching one hundred years of age, the mirror develops a soul and is transformed into a yōkai—a very common theme among tsukumogami.
Ungaikyō has also been portrayed as one of the many transformations performed by tanuki. By sucking in large amounts of air and inflating their bellies, a tanuki is able to display a picture on its bare belly similar to a television screen. This portrayal is not rooted in folklore however, but comes from Daiei Films’ 1968-69 yōkai movies. Nonetheless, it has caught on and remains a popular variation of ungaikyō in many productions.