This book tackles the question of border control in and around imperial Japan in the first half of the twentieth century, with a specific focus on its documentation regime. It explores the institutional development, media and literary discourses, and on-the-ground practices of documentary identification in the Japanese empire and the places visited aby its subjects. The contributing authors, covering such regions as Korea, Manchuria, Taiwan, Siberia, Australia, and the United States, place the question of individual legibility in the eyes of the respective governments in dialogue with the global developments of the identification and mobility control practices. The chapters suggest the importance of focusing more than previously on the narrative of individual identification, not as a tool for creating nation states but as a tool for generating, strengthening, and maintaining asymmetrical relationships between people of different socioeconomic backgrounds who moved in and out of empires. For those interested in migration history, this book addresses the field's heavy focus on the transatlantic world and the areas affected by European empires, such as Africa and South Asia. The book shows a complex interplay between state power and moving individuals, two forces whose relationships went far beyond simple competition. As the topic is relevant to contemporary readers including students, it offers engaging teaching material. Undergraduate and postgraduate courses on East Asian history, migration history, and the history of empires can especially benefit.