Around this time, it was becoming difficult to read the original text in the course of changing language and culture, so commentaries to add the study of poetry quotations and historical events, and explanations of difficult words were generated.
このころには言語や文化の変化や流れに従い原典をそのまま読むことも困難になってきたため、原典に引歌や故事の考証や難語の解説を書き添える注釈書が生まれた。