The Invisible Sabre

Chief Chao of the Wei Wu Society owns a powerful sword, called the Invisible Sword. The sword is coveted by many and one day the Society is massacred leaving almost none alive. The sword falls into the hands of a masked man who is unable to discover its secret. A surviving son of Chief Chao goes undercover in the masked man's gang in order to recover the heirloom and avenge the death of his family.
(Source: The Butterfly at MDL)