Since the mid-19th century, Japan and the United States have participated in political and cultural exchanges that have influenced Japanese identity. Americana in Japan is a useful means of analyzing Japan’s relationship with the United States and U.S. culture. I argue that Bluegrass music, which has been performed in Japan since the mid 1940s, as a kind of americana offers a particular articulation of imagined class-based, regionalized, and racialized articulations of U.S.-ness. These imagined articulations of U.S.-ness, both temporally contingent and enmeshed in broader cosmopolitan dynamics. By focusing on the imagination, I attend to the complex processes through which Japanese musicians and enthusiasts constitute their identities. To do so, I identify expressions of personal significance, communal meanings, and anxieties connected to participating in these music cultures. In this paper, I focus on divergent meanings tied to imaginaries cultivated within bluegrass music as a type of americana by highlighting periods of engagement that correlate with heightened geopolitical encounters between Japan and the United States, such as the Japanese anti-Vietnam war protests and accompanying Folk Boom in the 1960s-70s. I suggest that the history of bluegrass is also a Japanese history, furthering an ongoing conversation that repositions bluegrass as a global music. In doing so, I continue conversations within ethnomusicology that examine Japanese consumption and performance of transnational cultural forms while pushing back on overly particularizing discourses of Japanese cultural uniqueness.