This story contains mild spoilers for the film Parasite.

Bong Joon Ho never met a genre he couldn’t subvert. For almost 20 years, the South Korean director has been making movies that span every category. Memories of Murder (2003), the true-crime detective story that made him a star in his country, is notable for how it mixes melancholia with biting satire. The Host (2006), a huge crossover hit, breaks every rule in the monster-movie rule book and is all the better for it. Snowpiercer (2013) and Okja (2017), two English-language sci-fi allegories, are as funny as they are terrifying.

As Korean cinema has produced some of the most exciting filmmaking of the century, Bong has been at the forefront, taking wild swings with outlandish stories. But his new film, Parasite, one of the best of the year, is a thrillingly restrained work, largely confined to two locations: the homes of the wealthy Park family and the poor Kim family. It examines what happens when the Kims, one by one, start working for the Parks—after which the story develops in some shocking ways, a Bong specialty. The Atlantic spoke with the director about the development of the film, the way Parasite is playing to international audiences, and his approach to allegory and genre-bending. This interview has been edited.

David Sims: I know Parasite initially started out as a play. What was the genesis of that idea?

Bong Joon Ho: I have a close friend who’s a stage actor, and he suggested that I try directing a play. Of course, with theater, the space is limited, but for all my previous films we had a lot of locations—like, Okja starts in the deep mountainside [of Korea] and ends in Manhattan. So I was thinking, What story could I tell with just two houses? I came up with the idea of a poor house and a rich house, because at the time I was working on the post-production of Snowpiercer, so I was really enveloped in this story about the gap between the rich and the poor.

Aside from Snowpiercer and theater, I was fascinated with this idea of infiltration. When I was in college, I tutored for a rich family, and I got this feeling that I was infiltrating the private lives of complete strangers. Every week I would go into their house, and I thought how fun it would be if I could get all my friends to infiltrate the house one by one.

Sims: You’ve worked in the world of allegorical sci-fi and fantasy in recent years. Did you consciously want to move away from harder genre films while keeping up the allegory?

Bong: Sci-fi gives you the advantage of being able to say what you want pretty directly. Like, in Snowpiercer, that scene where Ed Harris has a long monologue in the engine car. Parasite has the landscape stone [a gift given early in the film that becomes crucial to the plot]. The movie has symbols, but I wanted to focus more on the mundane atmosphere, on the stories of our neighbors.

Sims: But Parasite still has the quality of a haunted-house story.

Bong: Yes, it’s still a genre movie, and there is some kind of ghost story. In this story, the characters treat a normal person like a ghost, so you can say that’s social commentary [and] a genre element. I think in my films, it’s always difficult to separate the two.

Sims: So many of your films are about people contending with monsters they don’t understand. That’s going on in Parasite as well; there’s a gulf these two families can’t breach.

Bong: I haven’t heard this comment in a while! If you think about it, my films are always based on misunderstanding—the audience is the one who knows more, and the characters have a difficult time communicating with each other. I think sadness and comedy all come from that misunderstanding, so as an audience member, you feel bad—you want to step up and reconcile them. As a filmmaker, I always try to shoot with sympathy. We don’t have any villains in Parasite, but in the end, with all these misunderstandings, they end up hurting each other.

The semi-basement home of the Kim family reflects their tenuous economic state. (Neon)

Sims: The design of the two houses is everything for the story—it sets up how these families exist so differently. How did you approach that?

Bong: Characters have to eavesdrop and spy on each other. So in terms of character blocking, all the structure was completed during the scriptwriting stage, and I had to basically force it on the production designer. So he felt a little frustrated, because the things I required aren’t things that actual architects would agree with. For me, they were a necessity to tell the story … but that gave [the production designer] an opportunity to focus on the texture and surface of the house, making it feel like it’s owned by this sophisticated, young, rich couple, and this is their way of showing off their taste.

For the poor house, the structure was relatively simple. But if the rich house feels like an isolated castle, the poor house couldn’t have any privacy, because this gap between rich and poor really draws from [access to] privacy. All the pedestrians and cars passing by had to be able to see inside the poor family’s semi-basement home. We had no choice but to build the entire neighborhood in a water tank because there’s a flood scene, so at the end we flooded the whole neighborhood.

Sims: Is that kind of structure, the semi-basement apartment, common in Seoul?

Bong: It’s quite common; you’ll see it pretty frequently in the back alleys of the city. But it’s also tied to the state of the protagonist: Semi-basement means you’re half above the ground, half beneath it. They still want to believe that they’re over ground, but carry this fear that they could fall completely below. It’s that limbo state that reflects their economic status.

Sims: The discussion about wealth inequality in America is very prevalent. Is that the same for Korea, that fear over the polarization between the rich and the poor?

Bong: There was another black comedy called The Big Short by Adam McKay; I felt a lot of things while watching that movie. And my friend Tilda Swinton, she filmed Only Lovers Left Alive with Jim Jarmusch, which was set in Detroit, a very industrial ghost city, so I did take in all these dramatic economic situations in the U.S. But I think the state of polarization applies not only to Korea but anywhere across the world. [South] Korea has achieved a lot of development, and now it’s a fairly wealthy country, but the richer a country gets, the more relative this gap becomes.

Sims: There’s a major turn halfway through the film. Did you always plan to structure everything around a big twist?

Bong: The second half of the film didn’t actually occur to me for the first few years I was thinking about this story. Then it all came to me, and I wrote like it was a hurricane. It’s always quite strange; through these interviews, this is when I look back on my writing process. I don’t understand how these ideas come up, how I end up writing them, so I feel like I’m not really in control of it. It just happens.

Sims: Certain images from the film have really stuck with me. There’s a moment where we see one character on the stairs, and he looks very frightening because of the new perspective we’re seeing him from.

Bong: Originally, in the script, it was not like that. It was, when the boy is eating a cream cake, there’s a reflection of that man in the window. But in the actual set design, the house was too big; the distance was too far—it would have been too awkward to create a reflection. So we had to change strategies. I like to bring my actors into the office to shoot photos of them. So I had a photo session with that actor and noticed that his eyes were so powerful, that I had to feature them. [Bong shows me a picture of the actor bugging his eyes out.] I really enjoyed this picture, I thought, Wow, fucking cool! Then I made this scene. There was no special effect—you just pinpoint lighting on him, and we just show his eyes. It’s like a pair of binoculars coming up from a submarine.

Sims: There are multiple objects in the film that mean different things to different people. There’s the sculptural rock, a “landscape stone,” that’s given as a gift and comes to represent all sorts of things.

Bong: To be honest, no one gives those landscape stones as a gift anymore. Perhaps my mother, or really older generations, but it doesn’t make any sense that young people would exchange that. But I always feel it’s more fun when I try to convince the audience of something that doesn’t make sense. In Korea, it’s very awkward that this young guy is gifting it. The film does justify it a little bit when the mom says, “You should have just brought food,” and her son says, “Wow, this is so metaphorical.” So even the characters think it’s weird. That rock is assigned this very unique position. It’s a kind of obsession for the young son. Throughout the film, he’s trying to imitate Min, his rich friend who initiated him into this world. Min disappears in this film after giving him the rock, but the rock is sort of the remnant of his character.

Sims: How is it seeing an international audience watch the film, where maybe they won’t understand a reference like that?

Bong: I’ve had some opportunities to watch the film with an [international] audience at the Cannes, Toronto, the New York Film Festivals. I’ve noticed the audience usually reacts the same—they laugh and gasp at the same moments. There are very subtle trivial details that [some] audiences won’t be able to understand, of course. For example, there’s a Taiwanese cake shop in this film; if you’re Korean or Taiwanese, you immediately know what that is. A lot of people who lost their jobs gathered money to open these franchise cake shops, and it was a huge trend for a while, but the businesses all failed, pretty much at the same time. So a lot of people suffered from these failures; it was a big economic incident in our society that Western audiences wouldn’t understand.

Sims: Song Kang-ho [who stars as the Kim father] often plays a sort of noble buffoon for you, an everyman, someone the audience can sympathize with. Was he always in your mind for this project?

Bong: It’s not as if I always write with him in mind because he’s a comfortable collaborator. I do give it a lot of thought, but because this film starts with a story of average neighbors and builds to something extreme, to cover that wide range, I thought Song Kang-ho would be the best to handle it. Especially in the climax; his character doesn’t have any lines—it’s the subtle changes in his muscles, the subtle tremors, that have to convince the audience of the entire film. Song has that strength as an actor.

Sims: Before this, you worked on a couple of English-language productions, and I know Snowpiercer was more fraught, while Okja offered more creative freedom. What was it like to return to the Korean industry?

Bong: With Snowpiercer, I didn’t have any issues during the production process. It was basically a Korean film with [English-speaking] actors, because it was produced by CJ Entertainment [the Korean company that also funded Parasite]. During the North American distribution process, we had some issues, but ultimately I got to release it as a director’s cut. Even with Parasite, it’s not as if I wrote this story with the intention to return to Korea. But once I settled everything, I did feel relieved, because I felt I could just have fun playing around with Korean actors in my native language. The budget was much smaller than Okja, around a fifth, so I felt like I could shoot the film with a microscope and focus on the really subtle details.

Sims: Would you want to go back to the scale of Okja, or are you more comfortable with the size of Parasite?

Bong: I love this scale and budget. That’s the reason my next two projects—one is Korean-language and one is Englis- language—both are relatively small, like this one.

Sims: Would you pursue working with Netflix again?

Bong: With Okja, we did have some issues figuring out the theatrical window of the film, but for the process of completing the film, I had their support. That’s why amazing films like Roma ,by Alfonso Cuarón, and The Irishman, by Martin Scorsese, are possible. I met Noah Baumbach in Toronto, and he told me he had a great experience shooting Marriage Story. I think all creators these days would be interested in a partnership with Netflix; now they have more flexibility, and [Netflix will] give you an exclusive theatrical window of four weeks.

Sims: What sort of stories are you looking to tell next?

Bong: The Korean film will be shot in Seoul. I don’t know if you can call it horror or action or thriller, but it’s based on a horrific incident that happened in the city. The English one is based on a true story, a news article from 2016. I’m still figuring out the story itself; I don’t know where it’s going to take me.

Sims: As you’ve been doing the festival tour and beginning Oscar season, has there been anything enjoyable about it?

Bong: I met Noah Baumbach and Adam Driver; recently I had the opportunity to meet David Fincher for something else. Those moments are always inspirational and a great joy. This is my first [Oscar] campaign, so it feels very unfamiliar and new and fun, but I think it’ll be my first and last. When will I ever do this again?