The crazy teenage bike gangs that terrorize urban Japan. They organize "races" through downtown Tokyo often during high-traffic periods causing accidents, often fatal to themselves and others. The "race" is not really a race since the leader, who carries the flag of the gang, cannot be overtaken. The other participants, who may number in the dozens speed in and out of traffic in attempts to slow down motorist and distract the police. Bosozuko are thought of by mainstream Japanese as thugs, predecessors of their older yakuza brothers, who actively recruit from their ranks.
The bosozuko rider opened the throttle on his modified Ninja to accelerate through a red light at 120 miles per hour, only to be creamed by a delivery truck in the intersection.