This feature article from Japan Times includes more perspective on filming in Japan and the cross-Pacific cast.

For decades, Japan had a reputation as a difficult place for international productions to film. But the experience of “Monarch: Legacy of Monsters” suggests that perception is beginning to shift.

“It was nice to see how everyone was coming together (and that) Japan is also growing to be a more easily filmable place,” Sawai says.

Ren Watanbe, who plays Kenark Randa, says:

“That’s what makes this show original,” Watabe says. “My character, who’s authentically Japanese, is bringing that element to the story on a very Hollywood scale. You’ve got Kurt Russell and Kiersey Clemons (alongside myself) and I think that’s a very unique thing.”