Young Hero(1980)

A gang of thugs led by a ruthless bully (Hwang Jang Lee) has been terrorizing the residents of a small Japanese town for years, and the townspeople have finally had enough. But they won't stand a chance without the help of a local man's son who's been secretly studying kung fu. Now, it's a classic battle between good and evil, with warring factions throwing punches, kicks -- and insults -- with impressive skill.