Shen Yue was a little taken aback when he heard of the Yamaguchi-gumi, but when he learned that Fujiwara Norika was the daughter of the group's leader, things started to make sense.
He remembered the existence of the Yamaguchi-gumi.
The Yamaguchi-gumi is a legal and the largest criminal syndicate in Japan. Despite having gone through numerous generational changes and outwardly resembling legitimate businessmen, any mention of the Yamaguchi-gumi invariably sent shivers down the spine of any businessman. This is because these people's business, if described in four words, can be called "tasting the blood of the knife".
They taste either their own blood or the blood of others!
The leader of the Yamaguchi-gumi is the head of this violent group, and the leader's daughter suggests that she is likely the heir to the violent group.
Of course, it's not the old-fashioned way now. Fujiwara Yabo can also be considered a businessman, and Fujiwara Norika is the heir to the family business.