Following the death of the Shogun, it becomes evident that his death was no accident. He was poisoned because he wanted his second-son to be heir to his throne. A battle between the eldest and his younger brother erupts. Warriors take each side swearing devotion to the prospective lords. The plot to pit brother against brother is secretly being controlled by the Yagyu clan, a group of warriors who have trained the Tokugawa shogunate's family in the art of swordsmanship for generations. A group of Imperial nobles are also secretly pulling the strings of this plot, hoping to weaken the power of the Shogunate and restore power to the Emperor.
This film was released in 1978 and stars Sonny Chiba and Toshiro Mifune. The plot of this movie surrounds the death of the second Tokugawa Shogun Hidetada. The movie is based on what is believed to have been a true rivalry between the real Tokugawa Iemitsu, the eldest son of Shogun Hidetada, and Tokugawa Tadanaga, the second son of Hidetada. In reality, Tokugawa Hidetada had abdicated rule to Iemitsu in 1623 but the movie plays it a different way from historical reality. In the film, Hidetada dies before naming his heir but apparently he had told several people that he planned on naming Tadanaga as his heir going against the tradition of naming the eldest son. The head of the Yagyu clan who was loyal to Iemitsu became aware of this and they did not agree with Hidetada's plan and therefore the Yagyu plotted to do something about it. So they assassinated Hidetada.
This is a Good movie with many, many good sword fighting scenes and political intrigue. The ending of the movie is also a complete shocker and is a total twist from historical reality. But it is interesting to imagine if this really happened historically. Conspiracy theorists would love this type of movie. This is one huge conspiracy theory.