The Tokugawa period saw a transformation in the systematic inquiry into nature. In the seventeenth century scholars were engaging in discrete fields of study, such as astronomy or medicine. But over the course of the next two centuries the fields that initially seemed distant and unrelated gradually converged into one enterprise that we now call “science.” Although Japanese scholars were not isolated from European science, it was not the outside influence that caused this transformation. Rather, the new conceptualization of science came from within, as different scholars came to align themselves along different lines. What brought them together was no longer social status, practical goals, or even their respective disciplines, but the kind of questions they asked, the kind of evidence they considered acceptable, and the sources they deemed authoritative. Together, they now engaged in Science, with a capital S, that was greater than the sum of its parts.

The acquisition of “Western knowledge” in late Tokugawa Japan, particularly in fields of science, technology, and medicine, has functioned as a central resource not only in modernization narratives but in the legitimization of imperial geographies that situate Japan as Asia’s rightful hegemon. This chapter brings together emerging research that decenters and pluralizes existing understandings of “Western knowledge,” placing “Western knowledge” instead within broader flows of global modernity. Specifically, by examining how a “transimperial educational commons” rendered diverse new texts and resources available to late Tokugawa scholars, this chapter argues that “Western knowledge” was in fact the product of networks of mediation across South, Southeast, and East Asia. Particular sites considered include circulation and brokerage through Dutch Indonesia and Qing China. The sum of these studies indicates that the problem of late Tokugawa engagements with Western knowledge can only be solved by examining sites both beyond the West and beyond Japan.