Kaidan (怪談) (sometimes transliterated kwaidan) is a Japanese word consisting of two kanji: 怪 (kai) meaning “strange, mysterious, rare or bewitching apparition" and 談 (dan) meaning “talk” or “recited narrative.”
Overall meaning and usage 
In its broadest sense, kaidan refers to any ghost or horror story, but it has an old-fashioned ring to it that carries the connotation of Edo period Japanese folktales. The term is no longer as widely used in Japanese as it once was: Japanese horror books and films such as Ju-on and Ring would more likely be labeled by the katakana horā (ホラー, "horror") or the standard Japanese kowai hanashi (怖い話, "scary story"). Kaidan is only used if the author/director wishes to specifically bring an old-fashioned air into the story.
Hyakumonogatari Kaidankai and Kaidanshu 
Kaidan entered the vernacular during the Edo period, when a game called Hyakumonogatari Kaidankai became popular. This game led to a demand for ghost stories and folktales to be gathered from all parts of Japan and China.
The popularity of the game, as well as the acquisition of a printing press, led to the creation of a literary genre called Kaidanshu.
Examples of Kaidanshu 
- Tonoigusa, called Otogi Monogatari (Nursery Tales) by Ogita Ansei (1660)
- Otogi Boko (Handpuppets) by Asai Ryoi (1666)
- Ugetsu Monogatari (Tales of Moonlight and Rain) by Ueda Akinari (1776)
Examples of Kaidan 
- Banchō Sarayashiki (The Story of Okiku) by Okamoto Kido
- Yotsuya Kaidan (Ghost Story of Tōkaidō Yotsuya) by Tsuruya Nanboku IV (1755–1829)
- Botan Dōrō (The Peony Lantern) by Asai Ryoi
- Mimi-nashi Hōichi (Hōichi the Earless)
Background of the romanized translation 
The word was popularised in English by Lafcadio Hearn in his book Kwaidan: Stories and Studies of Strange Things. The spelling kwaidan is a romanization based on an archaic spelling of the word in kana - Hearn used it since the stories in the book were equally archaic. The revised Hepburn romanization system is spelled kaidan.
Plot elements 
Originally based on didactic Buddhist tales, kaidan often involve elements of karma, and especially ghostly vengeance for misdeeds. Japanese vengeful ghosts (Onryō) are far more powerful after death than they were in life, and are often people who were particularly powerless in life, such as women and servants.
This vengeance is usually specifically targeted against the tormentor, but can sometimes be a general hatred toward all living humans. This untargeted wrath can be seen in Furisode, a story in Hearn's book In Ghostly Japan about a cursed kimono that kills everyone who wears it. This motif is repeated in the film Ring with a videotape that kills all who watch it, and the film Ju-on with a house that kills all who enter it.
See also 
- Japanese mythology
- Lafcadio Hearn
- Glen Grant
- Shigeru Mizuki
- Gakkō no Kaidan - School ghost stories
- Ghoul Power - Onryou in the Movies Japanzine By Jon Wilks
- Tales of Ghostly Japan Japanzine By Zack Davisson
- Japanese Ghosts Mangajin #40 by Tim Screech[dead link]
- Hearn's Kwaidan: Stories and Studies of Strange Things.
- A site with several kaidan.
- Asian Folklore Studies: The Appeal of Kaidan Tales of the Strange.
- Information on The Kaidan Suite, a musical interpretation of kaidan by the Kitsune Ensemble.
- Hyakumonogatari.com A website of translated kaidan