The country's largest crime syndicate, the Yamaguchi-gumi, may be splitting up as more than a dozen affiliate groups are expected to leave and form a new organization in the near future, investigative sources said.
The police are on higher alert as an inter-gang conflict could occur in the course of the expected breakup, the sources said.
A major conflict occurred in 1985 between the Yamaguchi-gumi and a group that seceded from it.
The Yamaguchi-gumi, founded in 1915 and headquartered in Kobe, operates through most of Japan.
It had about 10,300 members as of the end of 2014, or about 23,400 including "quasi" members, accounting for 43 percent of people estimated to be affiliated with gangs in Japan, the National Police Agency said.