
“Yokai, sir? Are they some kind of ghost?”
“They are spirits. Your language has no word to describe them precisely. Fairy, goblin, ogre, sprite—all of those come close, but none of them means quite the same thing. They dwell in the in-between places, the shadowy zones between land and sea, civilization and wilderness, night and day, life and death. Everyone in Japan has heard stories about them, but no one can see them unless they choose to make themselves visible. So, people who have actually seen one are rare indeed. Even among those who study the Way of Light and Shadow, only a very few have learned how to see a yokai who does not wish to be seen.”
– Simon Grey and the March of a Hundred Ghosts
This was the first time Simon heard the word “yokai,” even though he had already seen several of them without knowing their name. But you might already have heard it, and even if you haven’t, if you have any interest in Japanese manga, anime or video games, chances are you’ve either seen a yokai or a creature inspired by one.
Yokai is a catch-all term for the mysterious creatures that haunt Japan by night. Some of them are “ghosts” in the traditional sense, the spirits of dead people (also called yurei in Japanese), but not all. Some are the spirits of dead things: according to Japanese legend, if tools or other household objects lie unused for a hundred years, they take on a life of their own, and become creatures called tsukumogami. (When Marie Kondo advises her clients to say “thanks” to items before throwing them away, the unspoken reason may be that if you skip this step, the objects may become tsukumogami and come back to haunt you!)
Other yokai are not ghosts at all, but mythical creatures like elves or dragons – some monstrous, some merely mischievous, some friendly and helpful. They come in all varieties, with hundreds already classified and more constantly being discovered. If you should happen to see something strange in Japan and wonder if it might be a yokai, the Yokai Finder is a great place to go for clues.
For centuries, yokai were a source of both fear and fun for Japanese people. Yokai stories were the subject of paintings, woodblock-print books (the manga of Simon’s day), and storytelling parties where people would beat the summer heat by sharing stories that sent a shiver up the spine. From the eighth century all the way into the nineteenth, Japan actually had its own Ministry of Magic, the Onmyoryo, whose job was to deal with the vengeful spirits suspected to be responsible for hauntings, natural disasters, or other mysterious events. (About this ministry, and the magicians who worked in it, more to come.)
The Onmyoryo no longer exists, but yokai continue to capture the imagination of artists, storytellers, and other creators throughout Japan:
- Artists and animators like Shigeru Mizuki and Hayao Miyazaki have taken inspiration from the classical yokai collection and added their own original creations.
- Video games like Yo-kai Watch and Pokemon, and related manga and anime, draw heavily from yokai stories, both ancient ones and newly-invented ones.
- Japan’s first yokai museum recently opened near the city of Hiroshima. At the moment, their website is only in Japanese, but you can learn more from English-language papers and the impressions of visitors from abroad.
Many visitors to Japan like me have also fallen under the spell of the yokai, and several of them have made it their life’s quest to introduce yokai lore to the English-speaking world:

- Artist and folklorist Matthew Meyer, creator and curator of the Yokai Finder, has also published three books with original drawings of yokai and introductions to the stories behind them.
- The “Yokai Watchers” show on YouTube recently opened with a 20-minute sprint through the entire history of yokai in Japanese art, literature, and popular culture.
- Hiroko Yoda and Matt Alt have published an English edition of yokai illustrations and descriptions by 18th-century yokaiologist Toriyama Sekien, and written a field guide to yokai in modern Japan. If you should happen to visit Japan and encounter some sort of bizarre creature, this guide will tell you if it’s harmless or dangerous, and in the latter case, how best to defend yourself against it. You never know, it could come in very handy!

So now, while you’re anxiously waiting for the chance to read the story of Simon’s adventure among the yokai, you know where to go to become an expert! Thank you for coming aboard, and see you at our next port of call!