Flashbacks offer the answer. In her youth, Ochiba, known as Ruri (Mila Miyagawa), is the daughter of a powerful ruler and fast friends with the young Mariko (Mana Nakamura). But Mariko’s father, the samurai Akechi Jinsai (Yukata Takeuchi), is aghast at the brutality of Ruri’s father, as are other prominent nobles, including Toranaga. Acting almost certainly as part of a conspiracy, Jinsai assassinates the rogue lord, the shattering event Mariko described for Blackthorne in Episode 5.

The murder paves the way for the Taiko’s peaceful reign. But it is also a grave crime, one for which honor demands that Jinsai kill his family, then take his own life. As the only surviving family member, Mariko’s reputation is stained by her father’s treason.

We know that Jinsai married off Mariko to Buntaro, a poor match, to save her, but at this point Mariko believes she has been condemned to a shame-filled life she would rather end. Her survival is suddenly cast in a new light: Toranaga tells Mariko her father willed her to live so she could seek revenge one day.

So Mariko and Ochiba, once friends, find themselves on opposite sides of the coming war, both are driven to avenge their slain fathers against surviving enemies. In a conversation with Toranaga, Mariko says that unlike men, who can pick and choose their reasons to go to battle, “a woman is simply at war.” Indeed, it does at times seem like conforming with feudal Japanese ideas about propriety is a lifelong physical battle. But for these two women specifically, war has raged inside them for decades. Even when no one’s being killed, they carry the conflict.

With Ochiba back in Osaka and free to boss the Regents around, Toranaga knows it’s only a matter of time before his death sentence is finally approved. In a genuinely exciting council scene featuring all his top advisers, save Blackthorne, Toranaga contemplates his strategy. A consensus grows that his next move should be a top-secret contingency plan dubbed Crimson Sky: a single, all-out attack on Osaka Castle designed to simultaneously wipe out his enemies and institute a new government with Toranaga as its head. “Shogun,” his awestruck son whispers in delight.