This article examines perceptions of the samurai and bushido in twentieth-century Britain. It does so by focusing on four key moments: Japan’s victory in the Russo-Japanese War (1905); the seppuku of General Nogi Maresuke (1912); Japan’s escalating militarism in the 1930s and 1940s; and the seppuku of novelist Mishima Yukio (1970). I explore the discursive variations across these four moments to demonstrate that British attitudes toward the samurai cannot be understood without situating them in the shifting geopolitical and ideological context of the global twentieth century. More specifically, the article highlights the centrality of questions of temporality. I show how British politicians and intellectuals at the beginning of the century associated the samurai and bushido not with medieval Japan, but with a utopian, progressive vision of the future (that is, an “alternative modernity”). Japan’s escalating militarism subsequently generated other interpretations, including the idea of bushido as a cause of Japanese atavism. But across these shifting British debates, one consistent objective in reflecting on Japanese warrior culture was to articulate explanations and predictions for the behavior of modern Japan as an international actor. Such discussions consequently also became opportunities for British elites to affirm or denounce particular visions of the sociopolitical order. Britain’s preoccupation with the samurai, then, amounted to much more than a timeless exoticist fascination with an Oriental culture. To debate the figure of the samurai was to evaluate the promise and limits of alternative modernities beyond the liberal Western model represented by Britain.