This study explores trade in northern Japan, predominantly on the island of Hokkaido, between the Japanese and the native Ainu during the Tokugawa period (1600-1868). It highlights the role that ecological change, epidemic diseases, and "reinvented" ritual traditions played in the breakdown of Ainu autonomy and Japan's conquest of Ainu lands.

By focusing on the role of ecology and culture in the conquest of Ainu lands, this study promises to identify early modern forms of Japanese colonialism, while introducing a broader East Asian perspective to the study of eighteenth-century Japan, a period still referred to as the "Closed Country" by some historians. Moreover, rather than view Hokkaido as the "frontier" of the Tokugawa polity, "open lands" ripe for development, I approach the topic from the perspective of Ainu and the local ecology, as well as the Japanese. I assert that the roots of the Japanese colonization of Hokkaido lay in changes in Ainu productive systems, ritual traditions, and the local environment, all sparked by the normalization of trade with Matsumae domain.

The theoretical approach used in this study resembles recent studies of the American West by historians such as Patricia Limerick and Richard White. I have also been influenced by recent environmental historians such as William Cronon and Alfred Crosby. The research was completed under a Fulbright Fellowship at the Research Center for Northern Studies, Wokkaido University Library. I also benefited from archives at the Hokkaido Prefectural Library, and the Hakodate Municipal Library, all located in Japan.

This study, aside from refuting conventional assumptions about the present shape of the Japanese archipelago, complicates the notion of Japanese homogeneity and the relationship between culture and ecology. It also questions the basic idea of a singular, ethnic-based "Japanese" cultural order and historical narrative in the geographic space today called Japan.