Isekai

 Isekai  (Japanese: 異世界) (lit. "different world") is a subgenre of Japanese fantasy light novels, manga, anime, and video games revolving around a normal person being transported to or trapped in a parallel universe. Often, this universe already exists in the protagonist's world as a fictional universe, but it may also be unknown to them. The new universe can be an entirely different world where only the protagonist has any memory of their former life, as in Saga of Tanya the Evil, or one that they reincarnate in. It may also be one where a formerly virtual world turns into a real one, such as in Log Horizon and Overlord. You can watch Her:

Characteristic The genre can be divided into two types "transition into another world" (異世界転移, Isekai ten’i) and "reincarnation into another world" (異世界転生, Isekai tensei). In "transition into another world" stories, the protagonist(s) gets transported to another world (e.g. by traveling into it, or being summoned into it). In "reincarnation into another world" stories, the protagonist(s) is sent to another world after dying in the real world, often suddenly. Common methods of death including being run over by a truck, spawning the meme of "Truck-kun", a truck which appears in many Isekai series that sends various characters to the next world.

In many examples, the main character is an ordinary person who thrives in their new environment thanks to things normal in the real world being seen as extraordinary in the "other" world. This can be physical characteristics, such as hair or eye color, or normal, every day skills they learned in their previous life such as cooking, engineering, basic education, or medicine, which are far more advanced in the modern, real world than in the world they are sent to. In Sorcerous Stabber Orphen, an entire population of humans appeared in the magically created world was transported from Earth and got partially mixed with local dragon like Heavenly Beings.

While the protagonist of a classic Isekai work is usually a "chosen hero", there have been a large number of alternative takes on the concept. One trend is the protagonist inhabiting the body of an unimportant side character, or even a villain (as in My Next Life as a Villainess: All Routes Lead to Doom!). In these stories, the goal of a protagonist is typically to reform the character in order to avoid a bad fate or death, often being so successful that they become the new lead. There are even instances of protagonists becoming inhuman creatures, such as in That Time I Got Reincarnated as a Slime, where the protagonist starts as a slime with special abilities rather than a human, or even inanimate objects, like a magical Onsen. Others, known as " Reverse Isekai ", follow beings from a fantasy universe who have been transported to or reincarnated on modern-day Earth, including the anime Laidbackers and Re:Creators.

An offshoot of the Isekai genre is the "second chance" or "reincarnation" genre, where a protagonist who, upon dying, finds themselves transported, not to a different world and new body, but into their own younger self. With their new knowledge and older intellect, they are able to relive their life avoiding their previous pitfalls, such as Replay and The First Fifteen Lives of Harry August. Another offshoot of the genre include the "slow life" approach, where the protagonist was overworked in their previous life, so decides to take it easy in the next. Another offshoot is where the protagonist uses the new world to explore an interest, hobby, or goal they had in the previous world but where unable to achieve, such as studying or perhaps opening a business, like in Restaurant to Another World.

In many works, Isekai overlaps with the harem and LitRPG genres, where the protagonist gains the affections of several potential love interests, who may or may not be human. One example of this is Isekai Meikyū de Harem O.

Writing for the Journal of Anime and Manga Studies, Paul Price in his article "A Survey of the Story Elements of Isekai Manga" argues for the existence of four kinds of Isekai, based on Farah Mendlesohn's framework of organizing fantasy: "portal-quest", where the protagonist enters the Isekai via some kind of portal (Price sites Death March to the Parallel World Rhapsody as an example); "immersive", where no such portal exists and all the action takes place in the other world (Slayers); "intrusion", which are akin to reverse Isekai in which the fantastic enters the real world (The Devil Is a Part-Timer!); and "liminal", where the portal becomes a liminal space where the real world and the Isekai mix (Restaurant to Another World).

Early titles that could be called Isekai include El-Hazard and Fushigi Yûgi, in which the protagonists stayed similar to their original appearance upon entering a different world. Later titles such as Saga of Tanya the Evil and Knight's & Magic involved their protagonists dying and being reincarnated in a different world.

The .hack franchise was one of the first to present the concept of Isekai as actual virtual world, with Sword Art Online following in its footsteps.

The genre became so popular that in 2016, a Japanese short story contest banned any Isekai entries. The publisher Kadokawa banned isekai stories as well in their own anime-style novel contest in 2017.

A Brief History
"See also: List of isekai works"The Isekai genre is not very new at all. It has been prevalent for several centuries. The first possible isekai story in classic Japanese literature is Urashima Tarou (浦島 太郎). Written by Iwaya Sazanami during the Meiji Period, this fairy tale is about a fisherman transported to the underwater Ryugu-jo (竜宮城, 龍宮城) or “Dragon Palace” after rescuing a sea turtle. The fisherman spent some time in the castle with the princess Otohime. Otohime gave a tamatebako (玉手箱) or “jewel box” to the fisherman but forbade him from opening it. The fisherman decided to return to his hometown, believing he just spent seven days underwater, but soon, he discovered that centuries had passed, and he opened the tamatebako out of curiosity. Smoke burst out of the box and enveloped the fisherman, who quickly aged into an elderly man. Urashima Tarou was so popular that it received literary and animated adaptations. The first recorded animated adaptation of Urashima Tarou was in 1918.

The other known Western precursors of isekai stories were Alice in Wonderland, The Wizard of Oz, Peter Pan, The Chronicles of Narnia, and A Princess of Mars. These Western stories may have also influenced Japanese pop culture.

The first Isekai anime aired on television was Aura Battler Dunbine (聖戦士ダンバイン), a mecha anime created by Yoshiyuki Tomino in 1983. The first few Isekai anime of the 90s centered around female protagonists. Anime and manga series such as Fushigi Yuugi, The Twelve Kingdoms, The Vision of Escaflowne, and Inuyasha have female protagonists with a magical link to a fantasy world. They have melodramatic tones, romance, and a wide cast of interesting characters.

The early 2000s brought the concept of virtual reality to the Isekai genre, particularly the .hack franchise and the Sword Art Online light novels. Sword Art Online was later adapted into anime in 2012 and spawned several video games. At this time, the concepts of virtual reality and gaming were at the peak of popularity within the anime world. More light novels followed suit, copying the successful formula of Sword Art Online.

There was a point in the late 2010s when the Isekai genre became too oversaturated. The tropes and elements of the Isekai genre were repetitive for the sake of pandering to fans’ desires. A short story contest in 2016 by Bungaku Flea Market, an exhibition and sale of literary works held all over Japan, and Shousetsuka ni Narou, one of Japan’s largest contribution fiction websites, prohibited any Isekai-themed entries. In 2017, Kadokawa Shoten also prohibited Isekai stories in their novel writing contests.

Modern Usage
Isekai is one of the most entertaining, engrossing, popular, and profitable literary genres today. It allows readers to enjoy a power fantasy and escape from reality for a while. It’s a form of wish-fulfillment entertainment for anyone seeking bigger things in life. Isekai also has the potential to encourage young writers to make original and engaging stories.

Etymology

 * The word “ Isekai ” (異世界) is a compound word. It consists of i (異) or “different,” and sekai (世界) or “world.” Isekai literally means “a different world” or “another dimension.”