In the current Chinese book, "Junshiden," it is stated, 'The specter (yokai) was in the Imperial Court for a long time. The King asked Tui the reason. He answered that there was a big anxiety and he recommended to empty the Imperial room,' and the word yokai is used to imply 'a bizarre phenomenon that's beyond human understanding.'
-今の中国の書物『循史伝』に「久之宮中数有妖恠（妖怪）王以問遂遂以為有大憂宮室将空」という記述があり、「人知を超えた奇怪な現象」という意味で、妖怪という言葉が使われている。