Yakuza in Japan control a large proportion of the sex industry.
They have huge assets and are major shareholder in large Japanese companies and banks, hence the political influence.
When In Japan, you will often see magnets advertsiing phone dating, sex clubs inside pay telephone booths, street signs poles.
The gophers that place these magnets, work for the Yakuza. What they do is illegal, and they are instructed to run as fast as they can if the police catch them. If they are caught, they will not give any info. away regarding their Yakuza bosses. You risk death if you give any Yakuza info. to the police.
As a rule, the Yakuza do not employ women directly as the consensus is that they talk to much and cannot keep secrets.
If you work for Yakuza and you end up in prison, it is a Yakuza honour and upon release, you are promoted up the ranks.
Bottom line is, Yakuza is the name of a Mafia group and a good majority of their activities are illegal.
It is tolerated by the Government and Japanese authorities as it is considered to be included in Japanese culture.
Generally, the Yakuza is fine from a safety stance to the general public, but simply earn money by getting involved with illegal things.
Hopefully a YAKUZA boss will be reading this and give us a full insight