They are generally umbrellas with one eye and jump around with one leg, but sometimes they have two arms or two eyes among other features, and they also sometimes depicted to have a long tongue. Sometimes, but rarely, they even have two feet, as depicted in the yokai emaki such the "Hyakki Yagyo Zumaki."
In the Hyakki Yagyo Emaki from the Muromachi period, yokai that appeared as umbrellas could be seen, but in this emaki, it was a humanoid yokai that that merely had an umbrella on its head, and thus had a different appearance than that resembling a kasa-obake. The kasa-obake that took on an appearance with one eye and one foot was seen from the Edo period and onwards, and in the Obake karuta made from the Edo period to the Taishō period, kasa-obake with one foot could often be seen. In the yōkai sugoroku "Mukashi-banashi Yōkai Sugoroku (百種怪談妖物双六)" the Ansei era, a kasa-obake was depicted under the name "One-footed from Sagizaka (鷺坂の一本足 Sagazaka no Ippon Ashi?)." Among the many non-living or still object yōkai depicted in the "Hyakki Yagyo Emaki," only the umbrella yōkai can be seen to have remain well-known even after the Edo period, and it is said to be the most well-known yōkai of an object.
They frequently appear in legends and caricatures, and as opposed to how they are a yokai that is unusually well-known, they do not appear in any eye-witness stories in folklore at all, and it is not clear what kind of yōkai they are. Literature about them are not accompanied by folktales, and thus they are considered to be a yōkai that appear only in made-up stories or exist only in pictures. After the war, there was also the interpretation that they were an existence that was on the same level as manga characters. One possibility that has been thought of is that when Hyakumonogatari Kaidankai became popular in the Edo period, the story-tellers were requested to tell new stories and about yōkai that is not yet known throughout society, and thus they were a yōkai created by individuals.
For tools used in human life, there was the way of thought that, as months and years pass by and these tools become older, they have an ability to become apparitions. These are called tsukumogami, and some literature consider this yōkai to be one example of them, but it has not been confirmed that there are any classical literature or classical essays that verifies this.
After the war, they became a representative character for depictions of obake and haunted houses, and are frequently used as characters anime, manga, and movies that have a theme on yōkai, and are also generally doodled by children.
These are not kasa-obake, but in folktales, as an umbrella yōkai, in the Higashiuwa region, Ehime Prefecture, there is a story that a rain umbrella would appear in valleys on rainy nights, and those who see it would cower and not be able to move their feet. Also, in Mizokuchi, Tottori Prefecture (now Hōki, Saihaku District), there is a yōkai called yūreigasa (幽霊傘, "ghost umbrella") that has one eye and one foot like the kasa-obake, but it is said that on days of strong wind, they would blow people up into the skies.
- 村上健司編著 (2000). 妖怪事典. 毎日新聞社. pp. 119頁. ISBN 978-4-620-31428-0.
- 人文社研究部編 (2005). 江戸諸国百物語 諸国怪談奇談集成 西日本編. ものしりシリーズ. 人文社. p. 2. ISBN 978-4-7959-1956-3.
- 阿部主計 (1968). 妖怪学入門. 雄山閣. pp. 128–129頁.
- 京極夏彦 (2008). 多田克己編, ed. 妖怪画本 狂歌百物語. 国書刊行会. pp. 272–273頁. ISBN 978-4-3360-5055-7.
- 多田克己 (1990). 幻想世界の住人たち. Truth in fantasy IV. 新紀元社. pp. 303頁. ISBN 978-4-915146-44-2.
- 一柳広孝監修 (2008). 知っておきたい世界の幽霊・妖怪・都市伝説. なるほど!BOOK. 西東社. ISBN 978-4-7916-1568-1.
- 田神健一・奥津圭介・中村亜津沙編 (2006). アニメ版 ゲゲゲの鬼太郎 完全読本. 講談社. ISBN 978-4-062-13742-9 Check
- 造事務所編著 (2007). 多田克己監修, ed. 日本と世界の「幽霊・妖怪」がよくわかる本. PHP文庫. PHP研究所. ISBN 978-4-569-66887-1.
- 初見健一 (2009). まだある。 今でもわくわく"懐かしの昭和"カタログ 遊園地編. 大空出版. ISBN 978-4-903175-33-1.
- 水木しげる (1994). 図説 日本妖怪大全. 講談社+α文庫. 講談社. ISBN 978-4-06-256049-8.
- 村上健司他編著 (2000). 百鬼夜行解体新書. コーエー. ISBN 978-4-87719-827-5.
- 湯本豪一 (2005). 百鬼夜行絵巻 妖怪たちが騒ぎだす. 小学館. ISBN 978-4-09-607023-9.