Abstract

Summary Although the Copernican hypothesis is popularized in Japan by Shiba Kōkan's books published between 1793 and 1805, the whole of the conceptions of the Occidental astronomy remains unknown at that time to most of the Japanese. Through the publication of Ensei kanshō zusetsu in 1823, Yoshio Nankō does achieve posthumously the project designed two years earlier by his young disciple, Kusano Yōjun, to spread this knowledge widely among the society. The book is a great and unprecedented success. Well known nowadays for its appendix (Chidō wakumon) and the influence that its content, while claiming the mobility of the Earth, did exert on the propagation of the heliocentrism in Japan until the very end of the Edo period, the book also provides as we think an unexpected and completely new platform for classical science, being the emissary of certain concepts invented by Shizuki Tadao from his relentless studies of Newtonian mechanics. Once we briefly recount Yoshio's career and discuss the sources and the morphology of his work, we give some arguments towards it.