not sure if tv show or movie – something like a sinbad fantasy tale where someone finds a giant who has been doomed to hang by one hand from a ledge in a cave, imprisoned there by the ring on his finger set into the ledge. In return for freeing the giant by cutting through the ring with his sword, the character gets the large gem set in the ring

was in english – american/british? back in 50s, 60s? – very vague memory from my childhood