Netflix original film “Officer Black Belt” explores the world of probation officers -- a little covered topic in Korea -- with witty comedy and thrilling action sequences.

This coming-of-age comedy action “Officer Black Belt” revolves around Lee Jung-do (Kim Woo-bin) who has exceptional martial arts skills and goes on to assist probation officer Kim Sun-min (Kim Sung-kyun). The two pair up to keep an eye on criminals wearing ankle monitors.

Director Jason Kim (“Midnight Runners,” “Bloodhounds”) said he has known about the work probation officers do for quite a long time.

“I received this letter (from the city government) notifying that a criminal wearing an ankle monitor had recently moved into my neighborhood. That was the first time that I want to do some in-depth research into it. Then I asked people around like police officers and former cops who devote their lives to protecting people in society,” director Kim told reporters during a press conference held in Lotte Cinema Konkuk University in Seoul on Tuesday.

Both Kim Woo-bin and Kim Sung-kyun said they did not know about the job before shooting the project.

“It was very interesting for me to know about the job. It also gives me a sense of worthiness and sense of duty when I play the character with a new occupation (that I haven’t played before),” Kim Woo-bin told reporters.

“I also became known for this occupation through this movie. I didn’t know there was an institution (where probation officers and martial arts officers work) exists. At first, I thought they were very strict and serious people but this movie also taught me a lesson that they also have humane aspects,” Kim Sung-kyun told reporters.

In the movie, Kim Woo-bin is a martial arts professional having altogether nine belts in three different martial arts including taekwondo, kendo and judo.

“I couldn’t become that much of a talented martial arts pro in just three months, but I tried my best and practiced as much as I could, so I naturally exude a professional feel in Jung-do’s attitudes and gestures,” Kim Woo-bin said, adding that he also tried showing different aspects of Jung-do by gradually losing weight and through hair dying.

Director Kim said he focused on highlighting Kim’s action sequences by involving all three of taekwondo, kendo and judo.

“Because Jung-do plays three different sports, I tried to emphasize his sports-inspired footsteps, as well as thinking about whether he is going to show taekwondo moves, hold a stick in a fight or play judo (in devising action sequences),” director Kim told reporters.

For his flagship action choreographies which include delightful, rhythmical body movements, Kim said this time he wanted to give Jung-do the fun and cool skills of throwing objects.

“I wanted to add a little wittiness to Jung-do’s actions, so I have him a habit of throwing stuff. So I was able to devise the world’s first-ever action sequence involving a jar throwing, which I discussed a lot with my staff on how to minimize the wound through various rounds of tests and experiments,” he added.

“Officer Black Belt” will become available on Netflix on Friday.