1) they never commit petty crime against any pribate citizen unconnected with their dealings…they stick to high profit invisible crime and only show violence against their own triads as discapinary measures….gratuitous violence or open displays of excess violence to intimidate are thought to be barbaric. They do not make work for politicians and police with open dispalys of violent crime which shock the public and in return the police turn a blind eye to their rackets. These rackets are largely protection and extortion…so the Yakuza are set up to provide protection to clients the police cannot…just don’t miss your payments.

2) any “punk” or unauthorized street gang operating in Yakuza territory is quickly and quietly liquidated…this is why there is an absence of petty crimes like mugging, armed robbery, beatings and rape..entry level free-lancer crimes are not tolerated by the local Yakuza shateigashira…it is not so much the fear of the police…it is fear of the Yakusa which keeps punks in line….the Yakuza like a calm and serene base to operate in where visible crime is nearly non existent….street punks who challenge that unwritten cultural dictate usually end up “disappearing” and the police show little interest in “finding” them.

seems like a system which has served Japan well.