The word yakuza (good for nothing) is believed to be derived from a worthless hand in a Japanese card game similar to blackjack the cards ya-ku-za (eight-nine-three), when added up, give the worst possible total.It is believed that most members of yakuza are related to the burakumin which dealt with discrimination from the other citizens because of their jobs. It’s also widely believed that the yakuza are descendants of the groups that fought off Ronin, it is difficult to determine where they really came from but it is believed to be from one of those groups
The yakuza is a crime syndicate similar to the mafia but they have differences. One of those differences is the fact that yakuza are legal in japan because they are easier to regulate, but the police do know what crimes the yakuza commits and which crimes they make money from. Yakuza bosses unlike other mafia bosses such as Mexican drug lords, are not fugitives of the law.
They started off as small groups of bandits and the Ronin which were rouge samurais. The yakuza is made up of loan sharks, prostistution rings, drug trafficking and human trafficking and gambling. Kenichi Yamamoto is the founder of the Yamaken-gumi Yakuza gang, who were based in Kobe Japan, is the largest affiliate of the yama-guchi gang.
After the Kobe earthquake that happened on January 17 1995,it was the Yamaguchi-gumi who first came to the aid of the victims in the gangs home city. The yakuza follow a strict code of honor similar to the bushido code. They call themselves “chivalrous organizations’” because they help the communities if they need it, do not bother the civilians, and they just want to be left alone.
https://en.wikipedia.org/wiki/Yakuza
https://www.thoughtco.com/the-yakuza-organized-crime-195571#:~:text=Early%20Roots,two%20separate%20groups%20of%20outcasts.&text=The%20second%20group%20that%20gave,in%20Japan%20to%20this%20day