Which was the first isekai tensei anime?


Someone in SciFi exchange [Which was the first isekai tensei
story](https://scifi.stackexchange.com/questions/277169/which-was-the-first-
isekai-tensei-reincarnated-into-another-world-story) mentioned Yojo Senki
could be the first Isekai Tensei _anime_ (not counting non anime stories,
where the first "reincarnated into another world" story could be the american
Barsoom books). Is this really the case?

Which was the first isekai tensei anime?




By matters of technicality, [Legend of Heavenly Sphere
Shurato](https://en.m.wikipedia.org/wiki/Legend_of_Heavenly_Sphere_Shurato),
from 1989, could be considered the first isekai reincarnation (転生) anime (in
terms of Japanese anime). While the series starts out as a transmigration (転移)
series, the protagonist finds out that he is a reincarnation of an ancient
king (of the same name first name) that ruled this otherworld.

