Shinobi: Heart Under Blade

The story centers on the drama resulting from the rivalry between two ninja clans in feudal Japan. While living deep within the mountains, the two clans have honed their skills to superhuman levels, but are restrained by imperial decree from battling each other.
Four centuries of simmering tensions threaten to boil over when the Shogun requests the clans appear before him. Fearing that rebels may use the ninjas as instruments of insurrection, the nefarious Nankobo Tenkai plots to ignite the rivalry. Nankobo creates a contest in which the clans are forced to choose five of their best warriors to participate. Leading the two clans are Oboro, the granddaughter of the respected Iga clan matriarch, and Gennosuke, the son of the powerful Koga clan leader.
Early in the film, Oboro and Gennosuke meet and fall in love, unaware of their clan ties. When they are both selected to compete they are surprised to discover the truth about one another's identities. The saga that follows explores an improbable love, intertwined with a breathtaking, fearsome match between ninja heavyweights. The long-awaited battle is hardly a friendly contest - it's a duel to the death!