My research interrogates Japan’s early-modern foreign relations through the prism of Pacific and world history. I argue that a period of assertive Tokugawa experimentation with trans-Pacific commerce in the seventeenth century engendered a guarded response from Habsburg Spain, the latter hesitant to cooperate across the sea. I thus flip the script of a putatively insular Japan rebutting expansive Catholic powers. Research at the Historiographical Institute in Japan will help shepherd this project from completed dissertation to book manuscript. Related research will lead to the publication of an article recounting the fate and significance of the three vessels the Japanese built to cross the Pacific at this time. I will use the second year of the fellowship to develop my next book-length project, “Silver Archipelago,” which examines the “life-cycle” of silver as ore, bullion, and coin to present an integrated account of Japan’s foreign relations and domestic economy from 1550–1750.