Writer/director Choi Seok-Won makes his feature film debut with My Boyfriend is Type-B, a film that takes the ready-made, but paper-thin premise of blood type theory and spins that conceit into an entire movie. Thankfully, Choi employs two actors that make the gimmicky premise work, idols Lee Dong-Geon and Han Ji-Hye, both hailing from the popular K-Drama Sweet 18 and rumored to be dating in real life as well.

Lee Dong-Geon portrays title character Young-Bin, a handsome, macho, but totally obnoxious young man who begins the film by breaking off a relationship in a most ungentlemanly way: after waiting in a parked car so Young-Bin won't get a ticket, the girlfriend reads him the riot act upon his return, prompting Young-Bin to slip into the driver's seat, break up with her, and speed off, leaving his new ex-girlfriend stranded in the parking lot. From the get-go, Young-Bin is not exactly a class act.

On the opposite side of the spectrum is the beautiful Han-Mi (Han Ji-Hye), a meek university student looking for true love, but never seeming to find it. As is typical in this kind of film, the two meet purely by chance: Han-Mi accidentally text messages Young-Bin before literally bumping into him. Han-Mi, feeling that their fortuitous meeting is a sign that they might be destined for one another, decides to pal around with Young-Bin and see if there's any chemistry between them. Taken by Han-Mi's sincerity and her willingness to pick up the check, Young-Bin jumps at the opportunity.

But Han Mi's cousin, Chae Young (Shin Hee) isn't quite so enraptured with Young-Bin and tries to dissuade Han-Mi from pursuing him. The thing is, Chae Young is a professional dating consultant and a strong subscriber to blood type theory. According to her, any relationship between the mismatched duo would be doomed to failure because Young-Bin is a type-B male, which supposedly makes him arrogant, hardheaded, and generally a jerk, whereas Han-Mi is a type-A female, one who supposedly can't help being timid and obedient. But while Chae-Young predicts impending doom, the happy couple try to give love a shot, ignoring their supposed blood type incompatibility. But will they succeed?

As with any romantic comedy, there are ups and downs for the new couple, and the actors do well selling what is essentially formulaic fluff. Han Ji-Hye does a fine job portraying the ridiculously nice, cute as a button Han-Mi, but she really shines in scenes where her character finally stands up for herself and stops being such a doormat. Actor Lee Dong-Geon acquits himself rather well in the somewhat challenging part of Young-Bin. It's a tricky role to pull off; the character has to be annoying enough so that the audience can recognize that there's a problem, but at the same time, he has to be charming and sincere enough for viewers to feel that there's something salvageable in the relationship.

This is a balance that is struck throughout the picture - Young-Bin goes from the sweetest guy in the world to complete jerk and back again, sometimes in the space of one scene. In some respects, Young-Bin is somewhat of a repulsive character. He's notoriously cheap, selfish, and pouting, with a laugh that's more than a little bit annoying. And it doesn't help that Lee Dong-Geon seems to enjoy smirking in a manner strongly reminiscent of Edison Chen. But thankfully, Lee is a much better actor than Chen.

And oftentimes, Young-Bin's jerky behavior seems to have an underlying purpose, usually related to romance or just plain common sense. Young-Bin seems genuine in his affection, and beyond the hackneyed displays of romance (flowers, singing, etc), he's also prone to some unique forms of chivalry. When a teaching assistant bullies Han-Mi, Young-Bin takes revenge, but in a totally unexpected and utterly hilarious way. Another thing that gives the character more dimensions is the fact that Young-Bin is struggling to make ends meet, a situation which would put a strain on any relationship, incompatible blood type or not. Yet even as one can see justification or at least an explanation for Young-Bin's actions, there's also the sense that he's doing it for self-serving purpose, even when he's being "romantic." This tension between his true feelings and his selfish nature will probably keep viewers guessing, perhaps even after the credits roll.

Of course, these kinds of movies are predictable: boy meets girl, boy loses girl, boy fights to get girl back. There's even some crying (In a Korean film? No way!). But here, there are more than a few variations on that traditional theme sprinkled throughout the film to keep things interesting. Although a somewhat ludicrous childhood trauma is used to give Young-Bin a chance to prove his love to Han-Mi, it's refreshing to see that even in the "happy ending," things aren't tied up quite as neatly as one might expect. There's the suggestion that even if they do reconcile, Young-Bin's personality traits will always be an issue. In its finale, the movie seems to acknowledge that relationships, even those built to last, are hard work. How refreshingly realistic! Although by no means high art, My Boyfriend is Type-B is a glossy, overall enjoyable diversion involving pretty Korean people who overcome their problems in the space of ninety minutes. Whatever your blood type, that's gotta count for something. (Calvin McMillin, 2005)

• The movie that amuses Han-Mi, but bores Young-Bin so much that he has to flee the theater is Wet Dreams 2.