The Last Warrior (1989)

The biggest Japanese battleship "Yamato" is badly damaged in a battle and shall be repaired at a small island in the Pacific which is inhabited only by Gibb, an US American observation post, and a few aborigines with their priest. Gibb and young novice Katherine can flee, but are tracked by two Japanese soldiers. After Gibb kills one of them, the other seeks revenge in a sword duel.