Born Invincible (1978) on Netflix

Plot summary

Ming Tu is the lead student at the Lei Ping Kung Fu school. He and his schoolmates come upon two men of the Chin Yin Chi clan beating an old swordsman while his daughter watches; Ming Tu steps in and drives them away, though one of his fellow students is wounded. The pair warn that the clan will return. Ming Tu takes the swordsman and his daughter to the school, where the master shelters them. The clan's two chiefs then arrive and demand that the old man be handed over: Chin Pa, who carries a steel baton loaded with a blade, and Chief Chin, whose tai chi has made his body impossible to wound with a weapon. The master refuses.