Translated from Mizuki Shigeru’s Yokai Daihyakka
How are Yokai born?
It is said that the vast majority of Yokai are born from the emotions of human, especially the powerful emotions of fear, yearning or hate.
But there are other ways for a Yokai to come into being:
1. From the violence of natural disasters such as floods, earthquakes, windstorms or volcanic eruptions.
2. From the fear of dying accompanying disease and dire poverty.
3. From fear of animals, especially the terror humans feel at the prospect of being eaten by some beast.
4. From plants with lifespans that outstrip humans, like cedar and pine trees. It was thought that these trees would live forever, and there was a desire of humans to believe in something that had power over death, something indestructible.
5. From human belief in superstitions and stories, or the teachings of religions. There are things that scientific knowledge cannot explain, and it is there that Yokai are born.
Further Reading:
For more information about yokai and their meaning, check out:
百物語怪談会 Hyakumonogatari Kaidankai 
Nov 13, 2010 @ 13:18:48
This is a great blog! I became a little bit fascinated with Japanese folklore after watching Spirited Away. I picked up a copy of Kwaidan from Amazon and devoured it (not literally). I think the thing I enjoy most about Japanese ghost stories is that unlike western horror where those killed usually ‘had it coming’, people are killed by Japanese ghosts purely at random, or simply because they were in the wrong place at the wrong time. They couldn’t have done anything differently, and they couldn’t have known.
Mar 26, 2013 @ 10:07:01
This blog is so great! I hope you don’t mind, but I’d like to use some of this information in a presentation I’m doing on the Yokai.
I’m just wondering if you could clear something up: Are yokai personifications of the world we interpret without electricity or are they a case of anthropomorphism?
Mar 26, 2013 @ 16:23:23
You are welcome to use any of my info. All I ask is that people credit me when they reference the site.
And my answer to your question would be neither.
There’s no connection between yokai and electricity. Granted, yokai were suppressed during the Meiji period when Japan worked toward scientific advancement and generally shunned superstition, but they have remained relevant up to the modern era. The most recent yokai—the kuchisake onna—appeared in the 1970s. So yokai are very happy in a pre- or post-electrical world.
Nor are yokai simple anthropomorphism. Remember, the word “yokai” does not refer exclusively to Japanese monsters. Yokai translates as “mysterious phenomenon” and can be almost anything—a wind, a wave, a plant, etc … And most physical yokai, especially the ones created Toriyama Sekien, are just there for pure love of the weird and the strange. Some of them come from old legends and ancient mythology, but just as many were invented for the purposes of drawing a strange picture, or telling a chilling story. The Hyakumonogatari storytelling game was the spawning ground of many yokai.
If I were to say what yokai “were,” I would say they are a personification of Japan’s love for storytelling, and an embrace of the supernatural. Japanese people live with the supernatural much more so than Westerners. Shinto shrines are everywhere, and you can see little gods and monsters just about everywhere you go. Its a very visible part of the culture.
Jun 28, 2013 @ 08:31:12
Does that mean orignally most of the youkais are humans ?
Jun 28, 2013 @ 12:24:21
Not at all. Yokai are born of the emotions of humans, but they are not human themselves. Emotions are very powerful in Japanese folklore, and strong emotions can give rise to monsters.
Jun 28, 2013 @ 21:02:30
Oh . So they are actually monsters ? Wondering where do they come from.. >.<
And im curious where do youkais go if they are dead .
Jun 28, 2013 @ 21:49:02
You could use the word “monster,” but that doesn’t really mean anything specific. They are more like embodied spiritual energy, given form by whatever birthed them. As to where they go when they die … well, I don’t know. But I don’t know where anyone goes when they die! It’s something that has never really been addressed in Japanese folklore as far as I know.
You should check out some of my other posts on yokai. It might give you a better understanding.
https://hyakumonogatari.com/2012/10/26/what-does-yokai-mean-in-english/
https://hyakumonogatari.com/2013/02/05/a-brief-history-of-yokai/
Jun 29, 2013 @ 03:20:24
Thankyou !
Now i understand lil bit better . Sorry for asking so many question >.< This would be my last one .
Is it true yokai lives in youkai mountain which located in gensoyko ? And theres a moriya shine originated from outside world moved into gensokyo ?
Jun 29, 2013 @ 10:47:33
No problem! Always happy to answer questions!
About Gensokyo. It isn’t a real place, or even real folklore–just a setting from the Toho Project series of video games. I don’t really play video games, so I don’t know anything about it.
Video games and comics always make up their own rules, so yokai from video games and comics can be very different from yokai from folklore. Just like vampires in Western films are VERY different from vampires in folklore.
Jun 30, 2013 @ 08:03:12
Oh i see , For a moment i thought it was real ! XD
Thankyou so much for those precise explanations !
Awesome blog. Ganbatteh >u< !!