 Mabuchi moved to Edo in 1737 and in 1746 replaced Kada Arimaro as the authority on Japanese studies in service to Tayasu Munetake, the younger brother of the feeble regnant shogun, a position Mabuchi retained until 1760. Mabuchi produced essays on a range of topics, but the focus of his study during these years was a philological analysis of the Man’yōshū through which he believed one could learn the words and spirit (kokoro) of Japan before these were Sinified and thereby corrupted during the Nara period of the eighth century. Mabuchi depicted the Japan of the Man’yōshū as a natural arcadia ruled by the descendants of the kami who governed in accordance with a Way (michi) that conformed to the natural rhythms and dictates of nature (literally, “heaven and earth”) itself: