Beginning with the kanajo (a preface written in Japanese script) to the Kokin wakashu (Collection of Japanese Poetry from Ancient and Modern Times), which was written in the mid-Heian period, Japanese karon began to expand as a field, and kagaku began to flourish; in keeping with karon, research into the Manyoshu (an eighth-century anthology of Japanese poems) began.
平安時代中期に成立した古今和歌集仮名序で日本的歌論が展開されるようになってから歌学は盛んとなり、歌論と並んで「万葉集」の研究も始まった。