Isekai refers to a Japanese subgenre in both anime and manga, in which the protagonist character is transported, reincarnated or otherwise placed into a different world, that may be a parallel reality or an entirely new dimension.
The term literally means “otherworld” and it has two types of stories; “isegai ten’i”, in which the protagonist has transitioned into a new world, while the other type “isegai tensei” depicts the protagonist to be reincarnated into the new world.
The concept had been part of Japanese culture and literature since ancient times and the most popular folk tale of this theme is the tale of Urashima Taro, who after saving a magical turtle is transported to a magical, underwater world.
However, after spending a few days in the sub nautical realm, he has to realize upon returning to his home, that over 300 years had passed.
Apart from this story, other tales from Western Europe, such as Alice’s Adventures in Wonderland and The Chronicles of Narnia all influenced the subgenre to some extent.
The “isekai” theme had been part of the modern Japanese art forms such as manga and anime since the 1980’s, including titles such as Aura Battler Dunbine or Fushigi Yugi.
The most globally popular “isekai” is the 2001 Hayao Miyazaki film, Spirited Away, in which the protagonist is transferred into the world of spirits.
- Wikipedia – Isekai