The current chairman of the Japanese mafia is Kenichi Shinoda
There main headquarters are in Koba, some of their offices are labeled with a plaque.
The point is that it does not matter that everyone knows they did the crime in legal court, what counts is that you can prove it. Which is almost never the case.
They got Al Capone on tax evasion, cause thats what they could prove.
Crime bosses act with impunity, they didn’t murder that person, some lowly criminals did. You cant get a warrant to search their property for some reason and when you do the place appears to be unnaturally clean because the right people are in their pocket.
Japanese police could arrest the chairman of the Yakuza right now, lower level crime will spike from the chaos (because the yakuza employs them for less visible bigger crime) till someone else will take the chairman’s place and nothing will be different.