If you want to have a good sleep, darkness is preferable. However, a certain kind of darkness can force you to reopen your eyes and brings back tension to your relaxed body. Sleep, which was invited for this year's Cannes Film Festival Critics' Week, throws such nights into the life of a newlywed couple expecting a child. Su-jin (Jung Yu-mi), the wife, spends what is supposed to be the most peaceful moment of the day in fear due to her husband Hyun-soo (Lee Sun-kyun) exhibiting abnormal behavior during his sleep. Director Jason Yu, who worked as an assistant director for Okja and The Great Battle, and won the Korean Fantastic Short Film Award at the 22nd Bucheon International Fantastic Film Festival for The Favor, came up with the idea of this couple in crisis when he was about to get married. Upon hearing the news of his feature film debut being invited to Cannes, he woke up his sleeping wife in the early morning to share his joy. The film he made felt like a story of a person who fights with love, even in moments where love itself is threatened.  

I heard that you started watching a lot of movies during your military service and explored related career paths after being discharge.

My interest in films started through a literary and creative writing class I accidentally took a year before joining the military. I was an ordinary international studies student, but thanks to that class I was introduced to many good books and films for the first time. While writing my own stories, I became interested in the field of storytelling. But you are right, the time when I watched films most aggressively was during my military service. When I was on leave, I would watch 3-4 films in a single day at the theater. My unit gave me the label of "movie maniac", and staying true to that humble reputation, I pledged to make films after my discharge. (laughs)

Which films made you dream of becoming a filmmaker?

During my leave, I watched films like The Fighter by David O. Russell and Nameless Gangster: Rules of the Time by director Yoon Jong-bin. I also came into contact with films by directors Bong Joon-ho and Park Chan-wook, and I thought, "These are amazing people." The film that had the biggest influence on me was In Bruges by director Martin McDonagh. It’s this director who first made me want to make movies, who first made me imagine myself in the director’s chair instead of being part of the audience. Recently, I really enjoyed The Banshees of Inisherin. 

Your career path leading up to directing your first feature film has been a ride. While making short films, you worked as an assistant director for Okja and The Great Battle, and you were also credited as a sound coordinator for Along with the Gods: The Two Worlds. You also contributed to Burning and Maggie as a translator.

I’ve also did scripts for commercials and worked on sets for music videos. Ten years ago, I worked as a script supervisor for singer Lee Jung-hyun's music video V, directed by Park Chan-wook and Park Chan-kyong, but there was some misunderstanding about this story and it blew up over time with some people saying I worked under director Park Chan-wook. (laughs) It was a long time ago, and the whole shooting took two days, so Park probably doesn’t even remember me, but I value this as one of my early experiences on set.

Your short films Video Message and The Favor were also screened at festivals, and both films are formally audacious as they take advantage of limited situations.

Although I have only two films that were screened at festivals, I actually made about eight films with people from my club, friends, and military mates. At that time, I even filmed movies with my then-girlfriend, who is now my wife, using just a smartphone. Even if I admit the production quality was rather low, whenever I had an idea, I would film it, like, casually. All the scenes for The Favor were shot in my own room. At that time, I was working on the English subtitles for Burning but I had a strong desire to take a day off to shoot a short film. For that reason, whenever there was an opening, I would work on a project of my own under some constraints, and as I did so I think I never felt restless.

The press release that announced the wrap-up of Sleep in April of last year had a powerful opening line: "Who is the person sleeping next to you right now?" How did you come up with this story?

I would like to thank the PR director who came up with the fantastic tagline. My first goal was to create an interesting genre film. At the time I was writing the screenplay, I was about to get married, so naturally the premise of the married life with a newlywed couple pervaded the story. I wanted to see how a couple who truly love each other would overcome their issues as a couple after they are confronted to an obstacle coming from the outside.

Those obstacles were represented in the form of a sleep disorder.

In typical genre films, the protagonists would try to escape from a threat. However, if what is threatening you is someone you love and want to protect, you have no choice but to confront your fears head-on. The theme of sleep disorder in that sense was interesting as it provided as it gave this story something to set it apart.

Were you not concerned about the short title, which on top of that could potentially be associated with the notions of boredom or yawning?

I liked the minimalism of the English title, and I thought that by just dropping a one-word title as the Korean title, without any subtitles, it could pique the curiosity of the audience. I became aware of those concerns about the title too late, but I guess this must have been my unconscious contrarian thing to try to make the title so interesting that those keywords wouldn't even come to mind in association.

Any fan of Director Hong Sangsoo’s work will for sure look forward to seeing Lee Sun-kyun and Jung Yu-mi play as a newlywed couple. Did movies like On the Beach at Night Alone and Our Love Story influence your choice for these two actors? Also, compared to Kim Ji-young, Born 1982, this time it’s Jung Yu-mi who witnesses her spouse acting in a confused way.

I feel like I should admit that there was indeed some influence from Hong Sang-soo, but in reality, it wasn't a considerable one (laughs). Both Jung Yu-mi and Lee Sun-kyun have a wide range of acting abilities. Even when they perform in genre films, they have a tone that makes it feel very real. I thought that was exactly the substance needed a film like Sleep, so I was really hoping they would agree to participate. They told me they want to work again with me someday.

The artistic director of the Critics’ Week, Ava Cahen, also introduced Sleep as a "sensational film about a young couple when they are about to have their first child." Can you tell us more about the child in the movie?

In the early stages of the film, the wife, Soo-jin (Jung Yu-mi), is pregnant. Up until that point, they were just a couple, so it is easy for Soojin to turn a blind eye to the weird behavior of her husband, Hyun-su (Lee Sun-kyu). However, after giving birth, Soo-jin becomes afraid that Hyunsu could pose a threat to the child. The child becomes what motivates the couple to more desperately try to resolve their issues.

The interior of the apartment where the couple lives serves as the main location where the story unfolds. The characteristics of the space seem to resonate with the emotions you wanted to convey in the film.

Since 70-80% of our film takes place inside a house, we created a set for it. As the couple's situation drastically changes throughout the film, we divided the story into three acts, and the art direction varies greatly for each period. Simply put, the interior design of the house changes. We took this as an opportunity to showcase diverse looks with the set decoration and the direction. For the first act we tried to make that space look warm and cozy to underline Hyunsu and Soojin are in their lovey dovey period, while for the second act, which is defined by the birth of the child, we wanted to make it feel claustrophobic.

The lighting appears to follow a similar principle. The trailer is very dark. 

With the lighting director and the cinematographer, we agree on the principle that when it's dark, it should be noticeably dark. There are many scenes that are dark to the point you may wonder if it's still allowed. But this is a bold step we weren’t afraid to take.

Given the genre's codes, there are also the expectation that music and sound should play an important role. With your experience as a sound coordinator, I can assume you were meticulous with your approach. 

I oversaw sound during the post-production stage of Okja, and thanks to that experience, I also worked as a sound coordinator for Along with the Gods: The Two Worlds. I was the middleman between the director and the mixing studio, and I was conveying each other's requests. Feedback on music and sound effects alone would result in documents of more than 100 pages. With such training, there was no way I wouldn’t approach every sound effect with meticulous attention to detail. The sound in Sleep represents the psychological states of the characters, and I had that concept whereby the sound should at times be amplified. Even in ordinary situations, if that was a moment that was oppressive for Soojin, we emphasized the sound, whereas in situations where Soojin remained indifferent to heavy circumstances, we made the sound lighter. We also omitted some sounds that you would naturally expect to be produced by some events so that these moments would stand out.

Your film is also gaining a lot of notice after Bong Joon-ho called it "the most unique horror film and smartest debut film I have seen in the past 10 years”. 

Bong Joon-ho is also the first person who read the script for Sleep. I showed him the previous scripts I worked on too, but after seeing this one, he encouraged me, saying this film could make my debut. I would bother him for tips whenever I had any concern, and he would always give me some good advice. He often said I didn’t need to worry because I was doing well. This imbued me with a lot of confidence.

After Cannes, what kind of film do you want to make? 

My top priority is to make entertaining films. I also want to continue making films with good-hearted characters. I am interested in situations where good-hearted people get caught in unfortunate situations. I believe that when they have to deal with such situations, it always creates some warmth, regardless of the genre. I want to make films that can convey that feeling.