Shogun's Samurai (1978)

After the assassination of the second Tokugawa shogun, it's uncovered that he was poisoned by supporters of his son Iemitsu, who believed they could elevate him to power despite his stammer and birthmark, which hindered his reputation. As Iemitsu and his brother Tadanaga vie for control of the shogunate, the nation fractures into rival factions, leading to all-out conflict. Iemitsu’s mentor, Yagyu, who is determined to ensure his success, ultimately betrays everyone—including his own family—in his relentless quest to secure the shogunate for Iemitsu.