In Japanese legal terminology, Yakuza organizations are referred to as bĂ´ryokudan, literally violence groups. Yakuza members consider this an insult, as bĂ´ryokudan is a term which can be applied to any violent criminal. It is generally believed that most Yakuza members come from poor backgrounds or are on the margins of society.They mainly make their livings from unlawful activities, such as gambling, drugs, prostitution and extortion. For many poor people the Yakuza have become like a family that protects them. After the earthquake in Kobe the Yakuza arranged financial aid and even a helicopter for local people most effected by it. Many local business see the extortion money as a form of 'tax' and the police are sometimes reluctant to become involved.
It's common within Yakuza circles to tattoo themselves. Their tattoos can depict their clan's crest. Some Yakuza members tattooed a black ring around the arm for each crime they committed. Tattoos were a mark of strength (some tattoos can take over 100 hours to do) and were also a sign that they were unwilling to accommodate themselves to societies rules and norms. Although tattoos have become mainstream in Japan as well as around the world it is not uncommon for public onsen (Japanese baths) and some capsule hotels not to admit people with tattoos as was my experience in Japan. Many of the older generation still associate tattoos with the criminal classes which may be the reason you don't see to many people showing them off in public places.