Bakuto (博徒) were itinerant gamblers in Japan from the 18th century to the mid-20th century. They were one of the forerunners of the modern Japanese crime gangs known as yakuza.
Bakuto plied their trade in the towns and highways of feudal Japan, playing traditional games such as hanafuda and dice. They were mostly social outcasts of various stripes, living outside the laws and norms of society. However, during the Tokugawa era, they were occasionally hired by local governments to gamble with laborers, winning back the workers' earnings in exchange for a percentage.
Many bakuto covered their bodies with elaborate tattoos, which were often displayed by the shirtless dealer of a card or dice game. This fashion led to the modern yakuza's tradition of full-body tattooing.
As the bakuto organized into groups and expanded into other operations such as loan sharking, half of the groundwork for the modern yakuza was born. (The other half came from another group of itinerants, the tekiya or peddlers.)
Up until the mid-20th century, some yakuza organizations that dealt mostly in gambling described themselves as bakuto groups. But this was seen as outdated, and most were eventually absorbed into larger, more diverse yakuza syndicates. For example, the Honda-kai was a Kobe-based bakuto gang which formed an alliance after World War II with the Yamaguchi-gumi, but were soon overtaken by the larger gang.
Fictional examples of bakuto can be see in the Zatoichi Japanese film series, about a blind masseur who would often participate in bakuto-run gambling.