Aoyama Xiu Xin had two purposes for leaving his card.
The first was to prevent Old Yang's family from becoming the scapegoat for him, an honest man trying to make a living in a foreign land, and he couldn't just cause trouble and walk away without a care.
The second was to have the Fulong Gang's spokesman come to him.
Compared to domestic Violent Gangs like the Yamakawa Family,
it was easier to control foreign powers, and they were bolder in their actions than domestic gangs.
Moreover, if found too dirty after use, they could be discarded at any time without fear of being unable to shake them off.
The key point was that they were indeed fighters, and if it weren't for being outplayed in political background and power by domestic gangs, they would have long since jumped to the top as Japan's number one gang.
In the end, the underworld wasn't about fighting and killing,
it was about human relationships and worldly wisdom.
