Yodoko proposes a marriage

The nun is Yodoko, the Taikō's widow, sent by Ishido to fetch the Heir. Half-blind and preferring "the mist that surrounds me", she squints at the barbarian, bows to Yaemon as Kwampaku and coaxes him to his writing lesson. Toranaga recalls how he sidestepped the Taikō's offer of Ochiba's sister Genjiko and married her to his son Sudara instead. Leaning on his arm, Yodoko urges him privately to become sole Regent, even Shōgun, and adopt Yaemon as heir, promising Ochiba's support; he calls it treason and holds to the Taikō's will. Then she proposes he marry Ochiba herself. Toranaga thinks of the tigress who has plotted his fall since she was seventeen, of the Taikō's hundred barren pillow-women and the two sons only Ochiba bore him, and wonders whether the Taikō fathered Yaemon at all. Aloud he calls the idea an inestimable honour.

An old woman's visit carries the deepest strategic proposal in the novel, marriage to Ochiba, and Toranaga's reflection on Yaemon's paternity plants the doubt that licenses everything he later does. Clavell writes it as courtesy, the treason spoken by a nun and refused with thanks.