Motoori Norinaga
was a "kokugaku" scholar, poet and philologist during mid-Edo period Japan. Along with Kada no Azumamaro, Motoori Norinaga, and Hirata Atsutane he was regarded as one of the Four Great Men of Kokugaku and through his research into the spirit of ancient Japan through his studies of the "Man'yōshū" and other works of ancient literature he expounded on the theory of "magokoro", which he held to be fundamental to the history of Japan..Independently of and alongside his contemporary Motoori Norinaga, Mabuchi is accredited with the initial discovery of Lyman's Law, governing "rendaku" in the Japanese language, though which would later be named after Benjamin Smith Lyman.