What does it mean, and take, to repay the unrepayable? Located within global conversations on reckoning with colonialism and slavery, Unrepayable Debt examines attempts to account for the savage plundering of labor and life of people enslaved by the Japanese empire. Centered on a series of slave labor lawsuits where Chinese victims sought overdue justice in courts across Japan, Koga's ethnography reveals the labor of reckoning both inside and outside the courtroom. Unrepayable Debt shows how an unprecedented transnational collaboration among Chinese victims, their descendants, and Japanese lawyers and activists led to a sea change in the legal sphere. The lawsuits exposed not only the original violence, but the complicity and implication of contemporary societies in silencing the victims, leaving them unredressable for decades. Arguing against reckoning as a discrete event that brings closure through settlements, apology, or compensation, Koga demonstrates how reckoning entails intergenerational processes driven by new forms of indebtedness. Grappling with the nature and the scale of imperial violence and the prolonged and entangled processes of decolonization and deimperialization, Unrepayable Debt compels a rethinking of what redress, repair, and reconciliation mean, how they are practiced, and where accountability lies.