Abstract: Using fourteen government censuses and a wide variety of quantitative historical sources, I trace the origins of the Japanese putative outcastes. Sympathetic scholars have long described the group - called the burakumin - as the descendants of a 17th century leather-workers' guild. Members of the group suffer discrimination because their ancestors handled dead animals, they write, and ran afoul of a distinctively Japanese religious obsession with ritual purity. In fact, the burakumin are not descended from leather-workers. They are descended from poor farmers. Eighteenth-century Japanese would not have discriminated against them out of any concern for ritual purity. They would have discriminated against them because they were poor. The burakumin identity as we know it dates instead from the early 20th century. In 1922, self-described Bolsheviks from the buraku upper class lauched a "liberation" movement. To fit their group within Marxist historiography, they created for it a fictive identity as a leather-workers' guild. Within a few years, however, criminal entrepreneurs from the urban slums had hijacked the new movement. They embarked on full-scale identity politics, and generated the public hostility that has plagued the group ever since. The criminal leadership used discrimination claims to shake down local (and eventually the national) governments for ever-increasing transfer payments. Before the 1920s, prosperous member of the buraku had stayed and helped to build its social and economic infrastructure. After the 1920s, those burakumin who hoped to capitalize on the shakedown strategies continued to stay. Given the public hostility that the criminal leadership generated, however, those who preferred mainstream careers increasingly left and merged into the general public.