"Yakuza (ヤクザ or やくざ), also known as gokudō (極道), are members of traditional organized crime syndicates in Japan. The Japanese police, and media by request of the police, call them bōryokudan (暴力団), literally "violence group", while the yakuza call themselves "ninkyō dantai" (任侠団体 or 仁侠団体), "chivalrous organizations". ... " http://en.wikipedia.org/wiki/Yakuza
Ichi the Killer (2001, Japan) As sadomasochistic yakuza enforcer Kakihara searches for his missing boss he comes across Ichi, a repressed and psychotic killer who may be able to inflict levels of pain that Kakihara has only dreamed of.
This is an example of a 'Bakuto' which were illegal gamblers.The formation of the Yakuza is shrouded in mystery however it is believed that they were a combination 'Bakuto' and 'Tekiya'. The 'Tekiya' where peddler who sold shoddy poorly made goods(MS). http://en.wikipedia.org/wiki/File:Zatoichi_017.jpg