English Version
Thanks to GeGeGe no Kitaro, Yo-kai Watch, and other pop culture hits, Japanese yokai are familiar not only to older generations but even to small children. Many people know names like Konaki-jiji, the old man who cries like a baby, or Rokurokubi, the long-necked woman, but fewer people know how yokai themselves came to be.
Their origins are not especially complicated. In many cases, yokai were born from everyday life: they were a way to explain strange, unsettling things that people could not otherwise understand.
Born from everyday mysteries
Yokai were not necessarily created because someone saw a creature with their own eyes. Rather, they emerged as explanations for mysterious events in daily life.
In the past, people did not live in a world where science could explain as much as it does today. A creaking sound from a building, for example, might seem trivial now, but without a clear cause it could feel deeply disturbing. To give those experiences a reason, people began to imagine beings called yokai, and over time the idea spread: if something could not be explained, perhaps a yokai was responsible.
A figure such as Yamauba, the mountain hag, may have been connected to the fear of people disappearing after accidents deep in the mountains. Her existence has never been confirmed, but stories like hers may have helped people make sense of dangerous, unknown places.
Influences from China
It is not widely known among general readers, but many Japanese yokai are said to have been inspired by Chinese supernatural beings. Even famous figures such as the tengu are often said to have roots in China.
However, Chinese monsters and mythical beings often have a grand, heroic, or beastlike image. Japanese culture appears to have absorbed those influences while reshaping them into something more local, strange, and close to everyday life. That process helped create the distinct world of Japanese yokai.
Did yokai really exist?
Based on these origins, many yokai can be understood as imaginary beings created to explain mysterious phenomena. Some also seem to have functioned as warnings, such as kappa stories that taught people not to go near dangerous rivers or deep water.
For that reason, from a scientific point of view, yokai are usually treated as creatures of folklore rather than real animals or beings.
There are exceptions that leave room for imagination. Mermaids, for example, are sometimes discussed as if they may have once been human or based on human-like encounters. Still, there is no confirmed evidence that such beings existed. Scientifically, the conclusion would be that they did not.
Even so, yokai have a strong sense of romance and mystery. It feels a little harsh to tell children too plainly that they are not real.
How old are Japanese yokai?
If we include theories and early references, the history of Japanese yokai is extremely old. In the Kojiki, a text from the 700s, beings such as oni already appear. In that sense, the roots of some yokai go back more than 1,300 years.
One could even jokingly say that their “parent” was an editor or compiler such as Hieda no Are, though of course there are various theories.
In the Kojiki, however, these beings appear only in written form. Yokai seem to have begun spreading more widely later, around the Kamakura period. During that era, illustrated scrolls about Shuten-doji, one of Japan’s three great evil yokai, were produced. The Tale of the Heike, which features the Nue, also circulated. Shuten-doji later appeared in otogi-zoshi story collections published in the Edo period as well.
Then, in the following Muromachi period, the famous Night Parade of One Hundred Demons picture scrolls were created. Today, examples and related works are held not only by museums but also by private collectors.
How yokai differ from monsters overseas
Outside Japan, creatures such as dragons and demons are famous, and they often have a powerful fantasy appeal. Japanese yokai occupy a similar position, but they can feel more realistic, as if they might actually exist somewhere nearby.
Japan also has gods such as Amaterasu, but this article focuses on yokai because they feel closer to daily life.
Why does this difference exist? One reason may be that Japanese folklore often builds from ordinary, familiar phenomena. Even the written characters used for yokai suggest something strange or uncanny. Because yokai are rooted in daily life, many of them have a surprisingly realistic texture.
In contrast, many overseas traditions are shaped around gods, demons, or creatures that feel more distant from everyday reality. Urban legends such as Slender Man are an exception, but many famous examples, such as Greek mythology or the Cthulhu Mythos, are far more removed from the ordinary world.
That closeness to real life may be what makes Japanese yokai so memorable: they are not always hiding in distant castles or ancient ruins. Sometimes, they are imagined in the sound of a house at night, a dark mountain path, or the edge of a river where people knew they should be careful.
Japanese Language
ゲゲゲの鬼太郎や妖怪ウォッチなどで、年配の方だけではなく幼児でも知っている日本妖怪ですがいかにして生まれてきたのでしょうか？。「こなきじじい」や「ろくろ首」などの名前や何をするかなどはご存知の方が多いですが意外と妖怪自体の発足について知っている方は少ないです。とはいうものの複雑な事情があって生まれてわけではありません。日常から生まれた言葉ですので本記事で簡単に説明していきます。日常から生まれた。。日本妖怪は実際に姿を見たから生まれたというわけではなく 「日常の不可思議な現象に理由を付けるため」に生まれた者たち です。
昔は現代のように化学が発達した世界ではありませんので、建物からきしむ音がするなど今では何でもないようなことでも原因がわからず気持の悪い状態になっていました。そのためそれらの事象に理由をつけるために「妖怪」という存在が生まれ徐々に浸透していき、解明できない事象は妖怪のせいだという認識が広まったのです。実際山姥など存在が確認されていない妖怪は、山の奥深くなどで不慮の事故により行方不明になった者たちの原因として語られていると思います。中国が原型。
一般の方にはあまり知れ渡っていませんが日本の妖怪はほとんど中国の妖怪がモチーフにさえていると言われています。天狗などの有名な妖怪も中国出身と言われていますね。ですが中国の妖怪はカッコいいものが多く、日本人にとっては幻獣に近いイメージですので取り入れつつもアレンジを効かせて日本妖怪が出来上がったのでしょう。存在はしない。上記の説明から見ると妖怪の多くは不可思議な事象に理由を付けるため生まれたことになり、危ない場所に近づかないように（河童など）生まれた妖怪もいますので実際には存在せず空想上の生物であると言えます。
人魚などもとは人間であった可能性がある妖怪もいますが、実在した証拠がないため科学的な観点でみたら存在しない結論に至るでしょう。しかしロマンがありますので子供たちにはハッキリと言いたくはないですね。いつごろから生まれた。日本妖怪の歴史は仮説も含めればかなり古いと言えます。700 年代の書物である「古事記」ではすでに「鬼」などの代表格である妖怪が書かれていますので、元となった妖怪たちは 1300 年前から存在していたことになります。つまり妖怪の生みの親は編集者であった「稗田阿礼」などとなりますね。
（諸説あり）。しかし古事記では文字のみの登場ですので本格的に広まり始めたのはその後の鎌倉時代あたりからとなりますね。鎌倉時代には日本 3 大悪妖怪の一角である「酒吞童子」に関する絵巻物「大江山絵師」が。刊行されており、「鵺」出てくるが「平家物語」も刊行されています。（江戸時代に刊行された御伽草子も酒吞童子が出てきます）。そして次の時代である室町時代には有名な「百鬼夜行絵巻物」が作成されていました。美術館だけでなくコレクターなどの間でも多数所持している方がいらっしゃいます。
海外との文化の違い。海外ではドラゴンやデーモンなど男子の心をくすぐるような生物が有名ですが、日本で同じポジションに値する妖怪達は本当に存在するのではないかというリアリティさが違います。＊天照大神などの神様もいますが妖怪の方が身近にあるという観点から今回は省きます。ではなぜここまで違うのかというと、日本人は漢字からもわかるように日常に近い現象を基にする風習があります。そのため妖怪も実際に存在するかのようなクオリティになっているのです。。一方で外国の方は何らかの神様を崇拝している場合が多くスレンダーマンなどの都市伝説的な存在はありますが、多くは現実離れした生物となっています。
ギリシャ神話やクトゥルフ神話がいい例ですね
