A few years ago, I discovered the Japanese term, “Isekai,” which literally means “Another World.” It has become a popular subgenre of its own in Asia, and that popularity has spilled over to Western shores, through books, manga, and anime. It’s similar to what we call “portal fantasies.” There are some differences between isekai and portal fantasies, depending on how you define them, but their intersection covers a lot of ground. Generally speaking, these are stories of someone from our world who goes to another world and becomes some kind of agent of change (usually a hero, but sometimes… something else).
These have been a staple of fantasy stories since… well, forever, really. Even before such classics as Burrough’s Barsoom series, The Narnia series, The Wizard of Oz, A Connecticut Yankee In King Arthur’s Court, or Alice in Wonderland. Think “Jack & the Beanstalk” – the beanstalk is literally his portal to another world. There were lots of Jack stories, most of which are lost now, but many of them did have everyman Jack going through secret doors or pits or what have you into worlds of giants and / or dwarves. The Jack tales are part of an oral storytelling tradition going back for hundreds of years.
For some more modern examples of portal fantasies, think of the recent Jumanji films, or Neil Gaiman’s Coraline. Evil Dead 3: Army of Darkness is a cult-classic. A couple of great examples of this kind of film that you might not think of as being portal fantasy (or isekai) are Yesterday and Galaxy Quest.
Isekai stories tend to be from Asia (although that is changing), and have been a popular staple of light novels, manga, and anime for years. The original Aincrad (and Alicization) arcs of Sword Art Online are popular examples. Re: Zero, Mushoku Tensei: Jobless Reincarnation, The Rising of the Shield Hero, Ascendance of a Bookworm, GATE: The JSDF Fought There, My Next Life as a Villainess: All Routes Lead to Doom, KonoSuba, Overlord, and That Time I Was Reincarnated as a Slime are all good examples of modern isekai stories in anime, manga, and light novels.
A Character From Our World
This kind of fantasy is all about experiencing the wonder (and danger) of a new world through a viewpoint similar to our own, modern vantage point. For that, we start with a character from our world and our time. This does not mean you can’t have a character with a unique perspective or who comes from a different walk of life in our world–that’s half the fun. However, it should still be a character the reader from the author’s intended audience can relate to on several levels.
Many modern isekai stories solve this by taking a shortcut. The main character is a “reader-insert” character with very little personality of their own and a generic background. I’m not a big fan of this approach, but I guess it works.
The character shouldn’t be from a different time or place that would make their viewpoint too different from our own. For example, Captain Kirk is from a science-fiction background of his own, so his experience of a strange, new worlds wouldn’t be a portal fantasy or isekai. While John Carter may have been a great isekai / portal fantasy character back in Burroughs’ day (and so he’s grandfathered in just fine), his pre-WWI world is so far removed from our own that he’d not be a great candidate for a point-of-view character in these kinds of stories today.
Likewise, “Reverse Isekai,” where a character from another world comes to ours, and we get to see our world through a new perspective, would not really qualify. It is its own thing.
Finally, I’ve seen a couple of stories where the fact the main character is from modern-day Earth seems to have been tacked on to a more traditional fantasy. If you were to ignore the intro, the main character might as well be a native of the fantasy world. These stories are isekais or portal fantasies on a technicality only. It’s fine if the origins of the character fade into the background as the months and years go by in a new life in another world, but the character’s background should initially play a major role.
Going to Another World
What qualifies as “another world?” It’s a setting that is very different and separate from our own. Obviously, getting sucked away to the warring kingdoms of Mars, or a fantasy world of dragons and sorcerers or talking animals would qualify. So would going far back or forward in time, to King Arthur’s Court or to the distant future of various incarnations of Buck Rogers. Being abducted by aliens and taken into outer space is a classic. So is traveling to a “lost world” buried deep inside the hollow Earth, full of prehistoric creatures and forgotten magic or technology.
Whatever the case, the setting should be significantly different from our world–at least from the perspective of our main character. That might not necessarily mean it is a significant difference for the reader. As an example, take the film, Yesterday. In the movie, the main character is injured in an accident where all the world’s electricity stops working for several seconds. When he awakens in the hospital, at first everything seems normal–but he soon gets suspicious of things not being exactly as he remembers. Then he discovers that the Beatles never existed in this world, and their songs were never written. As a struggling musician inspired primarily by the Beatles, whose only claim to fame is doing covers of Beatles songs, this is a huge difference between the worlds.
“Hidden” worlds – like the wizarding world in Harry Potter – usually don’t count. While the character can experience the same sense of wonder, they never really leave our world. Traveling to another world requires some level of commitment. Being able to jaunt around through time and space in a magic blue box is also not really the stuff of true portal fantasy or isekai. In GATE: Thus the JSDF Fought There, however, while the titular gate is a fixed location and crossing over is a short walk or drive through, the military occupation and tight government restrictions make going back and forth a serious undertaking. It counts. Spirited Away is more questionable as an example of the subgenre. The setting is more of a hidden world within our own, but the main character must not leave as a matter of her own sense of duty and love of her family.
Agent of Change
The characters from modern Earth (or a very similar equivalent) in both isekai and portal fantasy tend to come with some ability or skills that not only allow them to survive in this new world, but to exceed what the natives are capable of doing. Or, in isekai terms, to “cheat.” This could be simply be from having “lost” knowledge or familiarity with technology, having skills only available from Earth, their Earthly or spiritual heritage, and / or special supernatural powers (possibly gifted by the beings responsible for transporting the character in the first place).
For example, John Carter possesses immense strength and can leap tremendous distances in the low-gravity world of Barsoom (Mars). He also has an outsider’s perspective and a sense of honor from Earth that enables him to attack problems from a different angle than the natives of the world.
In Re: Zero, the hero is categorically worse at most things than any adult native, with (at first) little self-awareness and extremely poor survival skills. The one ability that allows him to endure is also the one ability that allows him to pull off the seemingly impossiblewhen he dies, time ‘resets’ a la Groundhog Day, allowing him to attempt to fix not only the situation that led to his demise, but also other mistakes he may have made along the way.
In Ascendance of a Bookworm, the protagonist threatens the entire social order with her “inventions” (and magical capacity), in spite of her frail physical form. In Yesterday, the main character disrupts the entire music industry with his “original” compositions. “User” Kevin Flynn’s adventure forever changes the computer world of Tron.
Adventure vs. A New Life
In portal fantasy, the adventure to a new world is often more of an extended visit. The main character accomplishes their objective and returns to our world a changed character, bringing with him or her the new skills and perspective they obtained on their “hero’s journey” in another world. This extended visit might take years (although in Narnia, they return home to find they have not aged and very little time has passed).
In your average isekai story, the ability to return home and resume anything approaching a normal life is less likely, if not impossible. Many isekai heroes are actually reincarnated in this new world following their deaths back on Earth, while retaining their past memories, skills, and personalities. They must set out building a new life in this (currently) unfamiliar world.
This isn’t really a hard-and-fast rule differentiating the two, just more of a tendency.
What’s Fun About Them?
Isekai / portal fantasies work on several levels. They are naturally effective escapist fantasies, as the point-of-view characters have literally escaped the mundane world (often unintentionally) and are thrust into new adventures. The point of view allows us to engage our sense of wonder, and we as readers get to learn about the fantasy worlds organically as the protagonist does. There is no status quo to return to, so the main character is thrust into an active role immediately upon arrival. And, yeah, there’s wish fulfillment here: a nobody from the real world becomes the single most important person in another world.
How about my stories? Would I consider the Blood Creek Saga to be an isekai or portal fantasy series? I think there are definitely some elements of this subgenre there, inspired in part by the old Jack tales. If I really wanted to, I could probably get away with calling the series a portal fantasy, but that is not the focus of the story. The world of “Around the Bend” is a setting, but not THE setting.
So I’m going to go with “no,” but if you like portal fantasies, it’s at least in the same area code.
I do have a short story in Fantastic Schools Volume III that I believe is solidly in the portal fantasy (but not Isekai) category.
Would I write a full-on isekai-style story? I would, if I felt I had a strong idea that stood out in the subgenre. I think it could be a lot of fun.