This project delves into the processes of adaptation where Japan endeavored to construct a modern imperialist power through migration-led agrarian colonialism à la American conquest of the frontier. Central to this story was the intersection of transpacific Japanese migration and attempts at agricultural colonization inside the formal empire, which adapted to and drew on expansionist discourses of the United States and Japan. Thinking about transpacific migration in light of Japan's imperial formation enables us to tackle another oft-neglected instance of its adaptive colonialism. In the prewar era, the experience of U.S. Japanese immigrants as self-styled "pioneers" served as a powerful model and metaphor for Japan's settler colonialism in Korea and Manchuria. My research unveils how the examples of immigrant colonial endeavors in the U.S.-Mexican borderland were intertwined with state-sponsored agrarian developments in Japan's new "frontiers."