Officers took eight members of Ota Rengo, including 25-year-old leader Eiki Hateruma, and three members of Konami into custody for the alleged assembly of dangerous weapons during a confrontation on June 15 of last year.
All of the suspects have reportedly denied the charges.
On that day, members of Ota Rengo, wearing ski masks and carrying metal bats, gathered in front of JR Kamata Station in Ota Ward. The group then moved to a street in a residential neighborhood of Meguro Ward and fought with the Konami group. Four participants suffered skull fractures, according to TV Asahi (May 8).
Starting in 2010, police have considered the two groups to be technically defunct, but both continue with activities. The year before, Hateruma, who is also considered a member of the Inagawa-kai organized crime group, was arrested on assault charges.
In March, both groups were among those considered by law enforcement to be “semi-yakuza” as a part of an initiative that intends to strengthen the ability of the police to track the activities of the gangs.
Of the 11 suspects, only three will face charges, TV Asahi reported.