This 90-minute 1976 documentary film by award-winning screenwriter and director, Mitsuo Yanagimachi, follows the Bōsōzoku particularly the group called the Black Emperors.
The Bōsōzoku is a Japanese motorcycle subculture that has an interest for motorcycles and motorcycle customizing. They usually engage in illegal trade of parts and they remove the mufflers on their bikes to produce more noise (which, of course, annoys the police). Aside from all these, the Bōsōzoku are also famous for their reckless driving, weaving traffic, refusing to wear protective helmets and engaging in thrill races in city streets.
God Speed You! Black Emperor is a documentary film that follows this group during the rise of the Bōsōzoku movement. It particularly follows one member of the Black Emperor and how he is forced to face his parents after encountering trouble with the police.