In his 1980 film Kagemusha or Shadow Warrior, Akira Kurosawa presents the sixteenth-century Takeda clan engaging a lower-class thief to impersonate their recently deceased leader, Takeda Shingen. I examine Kagemusha as a critical engagement with Shakespeare's English history plays and ‘shadow’ counterpart to Kurosawa's trilogy of Shakespeare adaptations, Throne of Blood (1957), The Bad Sleep Well (1960) and Ran (1985). In keeping with Shakespeare's dramatisation of English history, Kurosawa creatively reworks historical sources, incorporating stories of intergenerational rivalry and fulfilled prophecies, to depict the transition from medieval civil conflict to the early-modern nation-state. Kurosawa also deploys the motif of the double to explore the distinctively Shakespearean theme of power as performance, engaging in a dramatic examination of Machiavelli's ideas about politics. I argue that Kurosawa's use of the double posits a theory of influence, drawing on Japanese cultural traditions, in which doubling can achieve a form of transcendence through self-annihilation.