My dissertation studies the development of transnational activism against racism and colonialism in East Asia and the United States from the 1920s through the 1950s. In particular, it examines the history of what I call "transpacific anti-imperialism," in which a variety of activists, including Japanese and Korean migrants in Asia and black, Asian, and Mexican Americans, influenced each other across the pacific, tackling Japanese and U.S. imperial powers. My project explores how distinctive racial and national identities of Korean and Japanese radical activists were constantly transformed and remade in migratory experience, intercultural encounter, and the shifting Japanese-U.S. imperial politics; and how such changing identities played central roles when the transpacific activists imagined, organized or abandoned political coalitions. In order to investigate such a transnational history of Korean and Japanese activism, I will conduct multi-sited archival research in South Korea, Japan, and the U.S. from September 2015 through August 2016. Analyzing a variety of primary sources including political pamphlets, newspapers, paintings, novels, and unpublished papers, I will examine how Korean and Japanese activists in both sides of the pacific forged global anti-imperial movements, where they exchanged ideas about emancipation from colonialism and elaborated their critical consciousness of nation and race, collaborating and often conflicting with each other as well as with different minority activists. Drawing on Korean, Japanese, and U.S. archival materials of anti-imperial activities and thought, my project will contribute to scholarships on social movements, race, and empire in English, Japanese, and Korean languages and provide with new perspectives to colonial histories and postcolonial transitions that still shape current political dynamics in East Asia and the Asia Pacific.