Wrath of the Koga Ninja (1960)

Corruption in the castle... the lord of the Mizorogi clan is dying. His heir, Young Lord Masayasu chained in an iron mask, deep in a water-filled dungeon by evil men determined to control the clan. His fiancée, Princess Mari searches for him, praying she's not too late. But Ryunosuke and the beautiful but deadly Oyuki, of the loyal Koga ninja will fight the corrupt officials, rally their last samurai and pit their deadly blades against the enemy in a final, desperate battle to save the rightful heir and restore the Mizorogi clan. Exciting ninja action highlights this clever tale from Daiei studio, showcasing realistic techniques and weaponry. Not to be missed.