This pathway describes the various transfers that resulted in the importation of the cowpox virus from Batavia to Fukui in Echizen province. It explores the interplay of vehicles and networks involved in moving this live substance along and accommodating its spatio-temporal characteristics. At the most basic level, the virus was carried by one of two types of bodily secretion—either fresh lymph or scabs. These secretions were able to cross long distances only when inserted into another vehicle—either a glass or tin container or the body of a child, which in turn had to travel by ship, on horseback, or on foot. Finally, various types of networks—ties between physicians, relationships between the Tokugawa shogunate and the domains, and trade relations between Japan and other states—determined where, when, and how the virus entered the Japanese islands and traveled from Nagasaki to Fukui.