Keichu established an empirical study method, and his academic achievements contributed to the development of early modern Japanology (Kokugaku) and became a landmark of the history of the study on the Japanese classics, thus greatly influencing the establishment of old kana orthography of the posterity.
また、その学績は実証的学問法を確立して国学の発展に寄与し古典研究史上、時代を画するものであり、また後世の歴史的仮名遣いの成立に大きな影響を与えた。