59 year old Setsuba Yamamoto, a member of the Matsuba-kai designated violent group drove a truck into Yamaguchi-gumi's office in Adachi, Tokyo.
After damaging the office building he dumped debris loaded on the truck in front and in the rival group's office.
Yamamoto surrendered himself to the police after his attack.
Police is investigating the struggle between 2 groups.

That is the formal designation, 指定暴力団.
Yakuza or 893 are informal names.

Real estate, construction, loan shark, entertainment and mizushobai is their main business.

The legendary speculator Ginzo Korekawa once said "Politicians afraid of Yakuza, Yakuza afraid of Police, Police afraid of politician; if you understand how to play this principle your life will be a success."