All they can do is prevent HA bikers from using their club logos for intimidation here, they couldn't win a case declaring the entire organization criminal.
The large biker crews here start puppet gangs now to do all the criminal activity so "Angels of Hades MC" end up being declared a criminal org with all it's assets seized, then they just make a new puppet org "Satan's Wings MC" and repeat.
I think the main difference is that there is more tolerance in Japan from the autorities. They consider it better to have Yakuzas than less "disciplined" and more independant criminals.
They haven't monetized theater grade law enforcement like the US war on drugs.
Its odd, because they probably could make make quite a few Yen by getting the population all wound up about a "war on yakuza" and militarize their police and build private prisons and flood their justice system with cases.
Clearly, enormous amounts of money have been made by monetizing policing in the USA, so there must be some interesting cultural difference that prevents that toxic meme from infecting Japan. Whatever it is, we could use some of those antibodies here.
