Yes and no. The genre of “other world” fantasy is pretty old. Wizard of Oz, Alice I wonderland, and going back further we find all manner of examples.
Even in antiquity we have stories that can be argued to be “other world fantasy” such as ancient tales from around the world of people entering the realms of god or various “afterlives” sometimes while living and sometimes not.
Of course the concept of reincarnation and being reborn in a different place or time and even keeping one’s memories are also quite old and well worn.
Arguably what is known as the modern fantasy genre started around the 1800’s and the closest recognizable roots to modern science fiction stem from around the same time, though there are examples of earlier works that can be argued to be in the genre.
So in that sense, there are plenty of American or western or other historical and modern Itsekai.
In another sense… maybe not? For example,
“Anime” is a Japanese localization of “animation.” It doesn’t inherently apply only to Japanese works. In that sense we could say sponge Bob or the lion king are “anime.”
“Hentai,” as many animated Japanese pornographic works are referred to, is also not a word inherently with that meaning, even in slang form.
Of course we run into some issues. The classic internet joke stems from word play on concepts such as how Champaign is not a type of alcohol in general but a name for a type from a specific region right?
In English we have our own words for various types of fiction.
Within fan and industry communities there are often worlds for certain genres of fiction or fiction meeting certain criteria- dark fantasy, high fantasy, hard sci fi, etc.
In American English we tend to classify things more by general genre, style, and composition than specific theme.
“Gritty thriller” “noir mystery” “epic” etc. the exact story elements or circumstances often only come into the equation when examining or deconstructing fiction.
In more recent times it has become increasingly common to append aesthetic elements- “post apocalyptic” “cyber punk” “alternate reality” etc. as appropriate- where for example the genre of speculative historical fiction is a catch all, there are nuances that can blur those lines as speculative fiction of course is fiction and may carry elements of fantasy but is generally thought of to be a more forensic affair- exploring likely or possible outcomes based in some measure of reasonable probability as opposed to alternate time line fictions which often explore more fantastic or less probable outcomes.
For example a work where the failed rise of communism led to a world where the UN held primary jurisdiction but was otherwise fairly mundane might be speculative historical fiction whereas a world where the failed rose of communism led to a UN dystopia with giant robots leans more into fantasy and might be considered an alternate world scenario. In an alternate world scenario the “what ifs?” And gaps to our current world in terms like technology and society tend to be much larger than is generally observed in human history.
So if one were Japanese one might call many works of fiction “itsekai,” and in theory there is nothing stopping the English language adoption of loan words, so we COULD use that word. In practice there is an argument that regardless of language the genre concept doesn’t really exist or have strong footing in the English language or concept of fiction at large. A kid transported to a fantasy world of knights and castles and such would generally just be called “fantasy” or “youth/young adult fantasy.” And we might say: “it’s a fantasy where a kid is transported to a medieval world.”
It could be that historically western fans of literature and fiction are less focussed in our interests. While there are those who enjoy and seek out time travel stories or space stories, stories of bleak technologically advanced futures, supernatural or some element like vampires or demons- our fan culture just tends to be different maybe. We generally don’t have the scale or scope of much Japanese..
… fandom. Until fairly recently, with rare exception, the western and especially American models for these things were very different. While America has long running franchises we don’t often have the long term story and character based continuity in fiction of Japan. Historically people rarely waited or kept interest En mass when it was years or decades between installments with rare exceptions that are mostly recent in the last 40 or so years.
Comic culture and cartoon culture still are and long have been very different and historically cartoons and comics weren’t seen by a mass public or media and corporate industries as “adult” or generally very lucrative outside of primarily child targeted animated films and shows.
It is also the case that historically the mechanism of “going to another world” hasn’t really been very “big.”
Don’t get me wrong- as said- enduring hits like Alice in Wonderland, Wizard of Oz etc. used this concept. Version of it or the same root hook can be found in much science fiction- visiting strange worlds or discovering worlds “within” our world- Journey to the center of the Earth, 20,0000 leagues under the sea, John Carter- works like Jumanji, it’s even common in time travel. Did Marty not spend the entire second film more or less, in a world that was “not his,” as explained by Doc- literally another world?
So it’s a common enough theme but it isn’t one people historically have sought out enough to carve its own genre of fiction in the US.
So call it as you like.
Even in antiquity we have stories that can be argued to be “other world fantasy” such as ancient tales from around the world of people entering the realms of god or various “afterlives” sometimes while living and sometimes not.
Of course the concept of reincarnation and being reborn in a different place or time and even keeping one’s memories are also quite old and well worn.
Arguably what is known as the modern fantasy genre started around the 1800’s and the closest recognizable roots to modern science fiction stem from around the same time, though there are examples of earlier works that can be argued to be in the genre.
So in that sense, there are plenty of American or western or other historical and modern Itsekai.
“Anime” is a Japanese localization of “animation.” It doesn’t inherently apply only to Japanese works. In that sense we could say sponge Bob or the lion king are “anime.”
“Hentai,” as many animated Japanese pornographic works are referred to, is also not a word inherently with that meaning, even in slang form.
Of course we run into some issues. The classic internet joke stems from word play on concepts such as how Champaign is not a type of alcohol in general but a name for a type from a specific region right?
In English we have our own words for various types of fiction.
Within fan and industry communities there are often worlds for certain genres of fiction or fiction meeting certain criteria- dark fantasy, high fantasy, hard sci fi, etc.
“Gritty thriller” “noir mystery” “epic” etc. the exact story elements or circumstances often only come into the equation when examining or deconstructing fiction.
In more recent times it has become increasingly common to append aesthetic elements- “post apocalyptic” “cyber punk” “alternate reality” etc. as appropriate- where for example the genre of speculative historical fiction is a catch all, there are nuances that can blur those lines as speculative fiction of course is fiction and may carry elements of fantasy but is generally thought of to be a more forensic affair- exploring likely or possible outcomes based in some measure of reasonable probability as opposed to alternate time line fictions which often explore more fantastic or less probable outcomes.
It could be that historically western fans of literature and fiction are less focussed in our interests. While there are those who enjoy and seek out time travel stories or space stories, stories of bleak technologically advanced futures, supernatural or some element like vampires or demons- our fan culture just tends to be different maybe. We generally don’t have the scale or scope of much Japanese..
Comic culture and cartoon culture still are and long have been very different and historically cartoons and comics weren’t seen by a mass public or media and corporate industries as “adult” or generally very lucrative outside of primarily child targeted animated films and shows.
It is also the case that historically the mechanism of “going to another world” hasn’t really been very “big.”
So it’s a common enough theme but it isn’t one people historically have sought out enough to carve its own genre of fiction in the US.
So call it as you like.