This article contains spoilers for episode 9 of “Shogun.”

Late one night, in the middle of shooting “Shogun,” Anna Sawai panicked. The actress had been struggling with her role as Lady Toda Mariko and couldn’t crack the precise emotional beats she needed for a tense dinner scene.

“I felt stuck,” Sawai says on a recent Zoom call from Japan. “You want to feel like you’re nailing it all the time. I’m always like, ‘I’m not doing it right!’”

She sought the counsel of series co-creator Rachel Kondo, whose experience with the script, and perspective as a half-Japanese woman, she hoped could unlock something. As production paused between takes, Sawai peppered her with questions. “She was just like, ‘Tell me what were you thinking,’” Kondo recalls. “Tell me about Mariko.” However, it wasn’t until Kondo spoke of her Japanese grandmother’s inner strength — she grew up on a sugar cane plantation and worked as a maid her whole life — that things started to click. “I think that just spoke straight to Anna,” she says. “She doesn’t understand things just with her mind, but with her whole heart.”

The brief interruption might have diminished another actress’s confidence, but looking back, the New Zealand-born Sawai recognizes that she’d been channeling her character’s inner strife.

“I think I felt that way because Mariko also felt very stuck,” she says. “She was in a position where she was lost, too.”

Indeed, throughout the majority of “Shogun,” FX’s 10-part adaptation of James Clavell’s 1975 novel, Mariko is a woman at odds with herself. Called upon by Lord Toranaga (Hiroyuki Sanada), an ostracized Japanese regent, to serve as an interpreter for his English captive John Blackthorne (Cosmo Jarvis), she is torn between her duties as a Catholic convert, a vassal and a daughter of a disgraced family line. Though the 17th-century drama, developed by Kondo and showrunner Justin Marks, centers on Toranaga’s political maneuvering, its conflicted heart belongs to Mariko’s journey to find purpose and meaning.

That existential reckoning finally crystallizes in this week’s ninth and penultimate episode, “Crimson Sky,” when Toranaga sends Mariko to Osaka to instigate his doomed master plan for supremacy. After being taken hostage by Toranaga rival Lord Ishido (Takehiro Hira) upon her arrival, she attempts to fight her way past guards inside the castle maze, knowing full well that her failed gambit will require her to commit seppuku, a suicidal act that will ultimately impugn Ishido’s leadership. Though he eventually stops her sacrifice, Ishido coordinates a secret assassination later that night, bombing a small shack where Mariko is trapped that leads to her fiery demise.

“It was the journey that Mariko had been making her entire life,” Marks says. “In a period piece like this, I see her as this real, true icon, able to weaponize her voicelessness at exactly the right moment, find dignity, and turn the tide.”

The all-encompassing episode called upon Sawai’s strengths as a martial artist, bilingual woman and actor of uncommon subtlety. In many ways, finding a performer with so many talents, capable of communicating and emoting in both Japanese and English, made the initial casting process for Mariko “the hardest journey of any of the characters,” Marks says. “It was like searching for a unicorn.”

“We wanted her to sound proficient and fluent and to feel that there was a dignity there, and that’s what she brought,” he adds. “She has this lone wolf quality that made her portrayal of Mariko unique and special.”

Ahead of shooting “Crimson Sky,” Kondo remembers checking in with Sawai about her state of mind. “I just gripped her by the shoulders and I’m like, ‘I’m worried for you,’” Kondo remembers. But by the middle of the episode, in the midst of repeatedly wielding her naginata (a long-shafted blade) against a samurai army, Sawai had descended into a focused trance. “She was a rock,” Marks says. “I’d never seen anything like it.” Thanks to a month of combat training before filming, Sawai wasn’t concerned with the action choreography so much as finding the right balance of poise and righteous anger that the performative fight deserved.

“We don’t really see Mariko showing her strength in that way — it’s always very concealed and very quiet,” Sawai says. “Whereas, this was the first time that we were going to see her kind of explode.”

The scene, which she played with a restrained anger, sets up a more solemn one, when she sits in front of family members and other vassals preparing to slice open her stomach with a sword. Sawai understood why her character undertook the brutal act. “Once Mariko figures out that that’s part of [Toranaga’s] plan, she’s ready to give her life to fulfill his needs,” she says. To find the right head space, Sawai mostly kept to herself, except for her personal costumer, who spent every morning wrapping her kimono’s thick layers around her.

“She came in with the most gentle atmosphere,” Sawai says. “On a day like that, everyone is just really trying to make sure that you have the energy that you need around you.”

On set, as she looked across the room, she locked eyes with Yuua Yamanaka, the actor who plays Mariko’s son, and unexpectedly inhabited the translator’s feelings of shame for causing her child to witness the event, just as she had witnessed the execution of her family years before. “That was a new finding for me, which was a very pleasant surprise,” Sawai says. In the minutes before contemplating her character’s suicide, she found that “seppuku had another meaning to it.”

After a brief action turn in 2021’s “F9: The Fast Saga,” along with higher-profile roles in Apple TV Plus’s “Pachinko” and “Monarch: Legacy of Monsters,” “Shogun” looks like a breakthrough for Sawai, who embraced her first time working on a jidaigeki (period drama). The restrictive, period-authentic costumes, she says, helped inform her choices over the 10-month shoot in Vancouver, while Sanada, a longtime actor and first-time producer, trained her to never meet his eye during their scenes together.

“It was odd getting used to it because it’s nothing like what we do when we try to connect,” she says. “Physically getting into the character really helped me kind of transform into her.”

As a kid, Sawai moved around — from New Zealand to Hong Kong to the Philippines — until her family settled in Japan when she was 10; her itinerant upbringing and her bilingual skills gave her exceptional insight into Mariko. “It wasn’t like ‘Oh, I don’t understand how she’s able to juggle these two languages,’” Sawai says. “It was just something that I already kind of did.” The familiarity of toggling between two cultures helped Sawaii have fun with — and contribute ideas for — a number of scenes in which Mariko slightly skews the meaning of the words she’s interpreting.

“Mariko is, in some ways, the absolute best translator. She’s also kind of the worst translator,” Marks says. “She’s very good at portraying what a person wants to hear. [Anna] really made the translation an event.”

Letting go of Mariko, especially as the show comes to an end, has been difficult for Sawai, despite the fact that filming wrapped nearly two years ago. “Her whole story was so heavy that it would affect my daily life,” she says. The actress notes she even began dreaming about Mariko, whose attributes, as she’s noted throughout her “Shogun” press tour, have transcended Hollywood stereotypes of female Asian characters.

“She kind of became part of me for those 10 months,” Sawai says. “I was crying in my interviews just thinking about her story.”

It might have been fate, then, that Sawai’s final day of shooting coincided with Mariko’s death, allowing her a joyous send off that didn’t require much acting beyond playing dead. “She was just all smiles,” Kondo says. “I think she finally could just breathe.”

Adds Marks, “It was the happiest person in full corpse makeup you’ll ever see.