This is a folk tale.

这是一个民间传说。

It could be a folk tale. It could be a history book.

可以是民间传说，也可以是历史书。

Folk tale is after many centuries passed down outstanding story.

民间故事是经过很多世纪流传下来的优秀故事。

This is a folk tale which is a story handed down orally among the common people.

这是在民众之中口头被递的下来故事的一个民间传说。

Later Akutagawa Ryunosuke wrote the novel Momotaro on the basis Of the folk tale.

之后，芥川根据这个民间传说创作了小说《桃太郎》。