On screen hit men and women have had a code — “rules” — going back at least as far John Woo’s “The Killer,” which folded into the early films of Luc Besson (“Nikita,” “Leon: The Professional). Besson added the idea that this unsavory profession required an infrastructure — “cleaners” who did the killing, with others summoned to “clean” the mess they made, safe houses, middle men, etc.

“John Wick” director Chad Stahelski and his writers added a hotel for hired killers, and borrowed that interantional guild of killers idea from the old movie “The Assassination Bureau.”

None of this resembles the real thing. You have to track down “The Iceman” to see how haphazard this “work” is and what dimwitted, psychologically-damaged mugs real killers-for-hire are like.

But those tropes and more are trotted out in “Kill Boksoon,” a Korean thriller about a lady hired killer on the Peninsula. It’s built around some epic fights, brawls extended because our titular heroine anticipates how this or that strategy, move or weapon will work against this foe’s “weakness” in any given situation. We see how things might go if she chooses wrong, and how the fight actually turns out.

Gil-Boksoon, played with a wary, timeworn resolve by Jeon Do-yeon — she was in “Emergency Declaration” — knows her business and has her code, which we see in a dazzling opener which has her dispatch a big cheese yakuza, giving him his Katana sword so that it can be a fair fight.

She’s the single mom of a secretive, somewhat rebellious teen (Mim Si-a). Mom’s high-paying gig allows the 15 year-old to go to a pricey private school, dropped off by Mom in her G-wagon. “Event planner” is what Jae-young thinks Mom does for a living.

Mom belongs to a Korean guild of contract killers, an organization we see set up, years before, in flashback. Various crews, including Gil Buksoon’s MK agency, run by its killer chairman (Sol Kyung-gu) and his creepy, smirking sister (Esom), set all this up so that amateurs, “the unemployed,” can’t sully their professionalism.

As if.

They use movie-making jargon to describe their work. A “show” is a contract, a person to be killed. The location of the hit is “the set,” etc.

Their rules? “Never kill anyone underage.” “Only take ‘shows’ sanctioned by your company.” And “You must accept ‘sanctioned’ assignments.”

There’s no calling in sick, no sudden attacks of morality are allowed. When that parchment assignment arrives under a wax seal, that’s your fate.

“Kill Boksoon” is about — you guessed it — running up against those “rules,” as Gil Boksoon tries to stay alive, please her boss. She must overcome office politics, proteges vying for her “A class” killer status, professional jealousy and the unique challenges of every assignment or attempted betrayal. That’s a lot.

And by golly, she must be a better parent, with a better mix between work and homelife

What this movie doesn’t have is “pace.” The intervals between brawls have some intrigue, a few attempts at parenting, and a growing sense of “stalling for run time” as they add a little to the story but are more notable for greatly testing the viewer’s patience.

The fights themselves are epic flurries of fists, tzinging blades and whizzing bullets.

Boksoon brings a “hatchet I bought online” (in Korean with subtitles, or dubbed into English) to a swordfight, anticipates blades getting knocked out of her hand, mid-fight, so that she can pluck them from mid-air to continue the tussle, or end it with a slice or a stab.

Writer-director Sung-hyun Byun (“Kingmaker”) gets all wrapped-up in world-building, showing us a crowded school for hired killers, having Boksoon put on a stage demonstration there, hearing her call “the cleaner” to tidy up a mess.

There are colleagues who are rivals and co-workers who are lovers, actually both at once.

And then there’s the parenting that’s being neglected as her daughter struggles through first love, school bullying and a chip-off-the-old-block gift for violence.

As this movie climaxes in a specialty hotel, it begs comparison with the “John Wick” films. But while the fights are terrific, they aren’t as epic as anything Keanu & Crew do, and they aren’t next-nevel furious, something Indonoesian and Thai thrillers and the Vietnamese “Furies” achieved.

I found the interludes tedious and the many different “versions” of how this or that fight comes out — anticipating the foe’s “weakness” and “next move” the way Robert Downey Jr.’s “Sherlock Holmes” did — cool, but confusing and a bit of a cheat.

Kill her off, or don’t. This isn’t “Edge of Tomorrow.”

There’s a joke, here and there amidst the mayhem, and a tendency to shift points of view a bit too freely.

One gets the feeling, re-watching this sequence to see what “really” happened or clock-watching through that interval awaiting something original, new or surprising to pop up, that there’s a better movie in this footage, if only there’d been less of it.

A tight 100 minutes is better than a slack 137, even if you need time to tell your daughter you don’t care who she loves.

Rating: TV-MA, graphic violence, sex, some nudity

Cast: Jeon Do-yeon, Lee Yeon, Esom, Hwang Jung-min, Mim Si-a and Sol Kyung-gu

Credits: Scripted and directed by Sung-hyun Byun. A Netflix release.

Running time: 2:17