The Perfect Warrior (1970)

On a remote island deep in the Orange Sea, an elite clan of warriors called the Totomé train and fight to keep peace among their lands. Every 100 years the top warriors compete to see who will take over as leader, or Abeoji. Katana and Sai are given this opportunity, but when their forbidden relationship is discovered their final challenge to become the leader is to fight in a Si Dou— a sword fight to the death.