Andersen Douwa Ningyo Hime (アンデルセン童話 にんぎょ姫),
or Andersen Fairy Tale: The Little Mermaid,
is a 1975 Japanese animated feature from Toei Animation.
Also the name of the second ending theme song (written in katakana, ニンギョヒメ) for the 2002 Chobits anime television series sung by Chii's Japanese voice actress Tanaka Rie (田中 理恵),
"Ningyo Hime" (「人魚姫」) - which literally means "Mermaid Princess" in Japanese - is the Japanese title for Hans Christian Andersen's famous fairy tale of unrequited love, The Little Mermaid,
or in the original Danish, Den lille Havfrue.
The sad, wistful 1975 Toei animated feature version of The Little Mermaid
is much closer to the spirit of the 1837 Andersen tale than the happy, joyful 1989 Disney animated feature version.
It is, in fact, I think even more sad than the Andersen tale, which at least ends with the hope of heavenly salvation for our lovelorn little mermaid princess.
(I've read that the original ending of the Andersen tale was far more sad, culminating with the Little Mermaid killing herself and dissolving into the foam of the sea, but Andersen was forced to tack on a "happy ending" by his editors who felt that it was too tragic for a children's story. In any case, the Little Mermaid's unrequited love is said to mirror Andersen's own very unhappy love life.)
A characteristically Japanese lyrical melancholy pervades Andersen Douwa Ningyo Hime,
as manifested in Marina's (the Little Mermaid's) beautiful but sad song of love, "Matteita Hito" (「待っていた人」), or "The One I've Been Waiting For," sung by Oosugi Kumiko (大杉久美子):
にんぎょ姫 (Ningyo Hime; The Little Mermaid)
Oosugi Kumiko / Matteita Hito (Full Version) from Andersen Douwa Ningyo Hime