The Amida assassin

An assassin in black scales the fortress by silk rope, garrottes a guard, gives the night's password and knifes two more, then bursts into Toranaga's sleeping room, where Blackthorne, lodged there on Toranaga's orders, kicks him off. Naga takes the man's head after he stabs himself crying "Namu Amida Butsu"; the Amida tattoo is in his armpit. Naga beheads the officer of the watch and is himself sent to Yedo. Toranaga tells Hiro-matsu the target was the Anjin-san, "worth ten thousand men", and the buyers were Christians; the ambush in the wood was his own staged play, and Friar Domingo has died in his cell. At dawn on the battlements, with the pregnant Lady Sazuko pouring cha, Toranaga questions Yabu about the Amida Tong, extracts Ishido's offer of Jikkyu's head, hears the plan for five hundred gun-samurai, and promises Suruga and Totomi. They seal it by urinating together from the parapet. Hiro-matsu calls his master bewitched. Toranaga laughs.

The night assassin pays off the ambush of chapter 15 and reveals Toranaga as the author of events the reader took for accident. Naga's double beheading and banishment measure the cost of a lapse in the household. The parapet urination is the book's grammar of alliance: intimacy staged as vulgarity.