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The Otherworldly Meaning of “Isekai” (異世界) in Japanese

The Otherworldly Meaning of “Isekai” (異世界) in Japanese

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Watching TV shows and movies in a foreign language you’re learning is a great way to practice your listening comprehension skills.

Unlike audio created specifically for learning, they feature people speaking at normal speeds and usually in a colloquial manner.

On the other hand, you can sometimes run into odd expressions that aren’t used so much in real life

If you’ve tried watching anime based on this, you’ve probably run into this problem before.

Indeed, there are a whole host of uncommon Japanese words to learn when it comes to anime fandom.

Sometimes these words are not just used in a particular show, but define whole genres or subgenres.

In this post, we’ll examine 異世界 (いせかい) and look at its definition and examples of use.


What is the meaning of isekai (異世界)?

異世界 is a noun that translates literally as “different world.” You might also see this term translated as “parallel universe,” “another world” or “other world.”

You probably won’t run into people using 異世界 in daily life. The term is most commonly used in anime, manga and light novels with a science fiction or fantasy focus, as well as video games based on those things.

“Other worlds” of the 異世界 variety are more likely to be fantasy-inspired and feature dragons, elves and other mainstays of fantastic fiction.

In a science fiction setting, however, the “parallel universe” translation implying a stronger similarity to our own universe might be more accurate.


What kanji are in isekai (異世界)?

Although there are three kanji in 異世界, the term is essentially made up of two words.

In this context the first kanji, 異, means “different,” although it can also imply “unusual” and a few other things.

You’re more likely to see this kanji in words like 異なる (ことなる), meaning “to differ” or 小異 (しょうい) meaning “minor differences.”

The second and third kanji together, 世界, mean “the world.” This is a pretty common word that should be familiar to most students of Japanese.

It’s worth noting that 世界 can also be used to mean “society” or a grouping of people, but in this context it definitely means world.

Putting these kanji together gets you 異世界, or “a different world.”

How do you pronounce 異世界?

Many kanji have different pronunciations depending on the word they are used in, and the 異 in 異世界 is no exception.

As noted above, when 異 is in the word for “to differ” its pronunciation is こと. This is the “kun yomi” or native Japanese reading for this kanji.

When combined with 世界, however, 異 uses the “on yomi” or Chinese reading, which is い.

世界 is always pronounced as せかい, so our pronunciation for this word is いせかい.

For rough pronunciation guidelines, consult the list below:

い – “i” as in “imp”
せ – “se” as in “sent”
かい – “kai” as in the sound at the beginning of the English word “kite”



“Anime that take place in another world are interesting, huh?”


“I want to be reincarnated in another world…”

As is probably obvious, this is not a word you’re likely to need in casual conversation.

The first example sentence is how to talk about media products which fit the 異世界 genre, while the second is the kind of wistful thing an anime otaku might say.


Some common types of isekai (異世界)

Although the word 異世界 is pretty simple to understand grammatically, the concept as it’s used in the light novel, manga and anime industry is full of variations.

At its core, the main element of a story in the 異世界 genre is one where the protagonist is transported to a world that is not our own.

However, there are numerous subgenres which still fit the definition of 異世界 while subverting it or playing up certain aspects.

It would probably be impossible to come up with a full listing of these, but understanding the context that Japanese fans of the genre will already know can help you apply the word properly to media you may be watching or reading.


Trapped in a fantasy world

In the late 80s and 90s, anime and manga were starting to become big business in Japan.

Perhaps as a result of that, some authors began creating “what if” style stories where the protagonists were normal Japanese kids who somehow got transported to and stuck in a world reminiscent of fantasy novels.

Because these stories got readers’ hearts pounding they were very popular.

These ideas aren’t unique to Japan. There are many English-language fantasy novels which fall into the category of “portal fantasies” about people traveling to fantasy worlds.

One prominent example is C.S Lewis’s series of Narnia books which begin with The Lion, the Witch and the Wardrobe, where a group of children travel through a cupboard to a fantasy world they must save.

Famous Japanese examples of this kind of story include Inuyasha, Magic Knights Rayearth and El Hazard.

Although the term 異世界 wasn’t used prior to the 2010s, these early predecessors of the genre also fit the definition commonly used for the word.


Video game worlds and isekai

The most recent explosion of 異世界 stories started with the publication of a light novel series called Sword Art Online in the mid-2000s and early 2010s.

In this series, a young man is trapped in a fantasy video game world that’s virtually indistinguishable from the real thing.

Sword Art Online spawned dozens of imitators and its impact has even spread to the English-language publishing world with the creation of a “RPG Lit” fantasy genre.

In these 異世界, the other world in question is some kind of video game. The protagonist may have been reborn into the “real” version of a video game world or in some cases may just be playing a virtual reality game that’s hard to tell apart from actual reality.

Light novels can be great to read, as they are written for a young audience and you can increase your knowledge of kanji without relying on too many difficult grammatical constructions.


Reverse 異世界

In typical 異世界, the protagonist travels to another world. In these inverted versions, fantasy characters end up in real life.

There’s a strain of 異世界 stories that veer into parody, playing with reader expectations of the genre.

The reverse 異世界 series The Devil is a Part Timer, where a demon lord flees a fantasy world to come to Tokyo and work as a part timer in a burger restaurant, is one of these.


The origins of 異世界

As noted above, the idea of traveling to a fantasy world is nothing new. One of the most famous stories about traveling to another world is Alice’s Adventures in Wonderland, written and published in 1865.

Japanese folklore has a long history of people being taken away to strange other worlds. The story of Urashima Taro, a fisherman who was taken to live in an underwater kingdom for 300 years, dates to the 8th century.

However, few people writing in English seem to be aware of the first actual use of 異世界 in Japanese writing.

That was 1981 science fiction novel 『異世界の勇士』 or Brave Warrior of Another World by Japanese author Haruka Takachiho (more well-known for the novels that led to the Dirty Pair and Crusher Joe anime series).

In this novel, the protagonist is summoned to a world where mysterious giant robots have destroyed everything.