In ‘Shogun,’ Anna Sawai Drew On the Power of Silence. And Mozart.

This interview contains major spoilers for Season 1 of “Shogun.”

When Anna Sawai was preparing to die, she listened to Mozart.

In a key scene of the FX series “Shogun” — in which Toda Mariko, the disgraced but defiant noblewoman and samurai she plays, meets her fiery demise — Sawai delivers a rebellious speech to the sinister Lord Ishido (Takehiro Hira). Lady Mariko knows it doubles as a death sentence. To prepare for this pivotal moment, Sawai said, “I was listening to ‘Requiem K. 626’ — ‘Lacrimosa.’”

The music, she said, gave her power. “It really helps you build,” she said in an interview last week. Referring to the director of the episode, Frederick E.O. Toye, she continued: “I remember Fred coming to me multiple times and asking, ‘Do you still have a couple more takes in you?’ I was like: ‘Yeah, this is totally fine. I feel good. Let’s do it.’”

Set in feudal Japan and based on the 1975 novel by James Clavell, the first season of “Shogun” focuses largely on the relationship between Sawai’s Lady Mariko and John Blackthorne (Cosmo Jarvis), the temperamental English navigator whose arrival in Japan triggers the conflict that drives the series. That conflict tests Mariko’s Catholic beliefs and her fealty to traditional Japanese customs against her desire for Blackthorne — and for justice against her oppressors. It also leads directly to her death.

“People are always like, ‘It must have been tough to prepare for that episode,’” Sawai said. “But I’ve been holding it in for 10 months, and I finally get to let go.”

It was the end for Mariko but not for Sawai’s relationship to the character: Her performance, almost entirely in subtitled Japanese, landed her an Emmy nomination for best actress in a drama. A fearless exploration of the emotional chasm between Mariko’s duties and her desires, it is all the more haunting for how much it leaves hidden.