Not bad enough to be a write-off, but personally I found it almost insulting. I blame the director. The actors are terrible and I hate them too, but the director's the one in charge and presumably gave a green flag to these performances.
I feel bad now about having criticised the acting in the other half of this 2009 Ju-on double bill, Shiroi Roujo, because almost everyone in that was perfectly okay and it was only in very occasional spots that you'd be made aware that you were looking at a gravure idol, not an actress. That film only really had one actress who was obviously not up to the job, but here it's the opposite. Kuroi Shoujo contains exactly one good actor. Her name's Yuri Nakamura, she's playing Mariko the Buddhist priest and my notes call her "the one who can act". It's almost startling when halfway through you realise that the film's introduced someone with screen presence, who's supporting the script with her performance instead of just saying the lines as themselves.
Apart from her, I wanted to say that the best performances come from the child actors. It's not true, but only because of little Hana Matsumoto's writhing during the exorcism. Koji Seto shows that he's not an actor, but he got the role because he's pretty and the lead vocalist of the J-Rock band TETRA-FANG. Ai Kago is better, making it up to the heights of "not very good", but she's still a former singer in Morning Musume best known for getting sacked for under-age smoking and being romantically involved with a 47-year-old. Maria Takagi is a ex-porn star. In fairness this kind of thing happens all the time in Japan and quite often these people eventually become competent as actors. However in this film, we're still waiting. The actors simply don't convince, for the most part being merely inadequate although there was one guy looking for his pet in the streets who I wanted to see beaten to death.
There are bright spots. I liked the bits involving the husband who wants to sleep around. That felt subtle and truthful, both when he's pestering the girl in the taxi and later with his tired, irritable relationship with his wife. However at the end of the day these are often-unlikeable characters being played by unconvincing actors, so we don't care about them. Bizarrely the film can't even hook us with a little girl in hospital, since she's a plot coupon rather than a character, unlike the children in Shiroi Roujo.
Then you've got the director. I've looked her up. She started out as an actress and assistant director for something that's either called "Ichi of Sodom" or "Sodom the Killer" in 2004. Sounds classy. She's never acted before or since in anything else, by the way. After that she directed Samurai Chicks, The Boy from Hell and Twilight Syndrome: Dead Go Round, then someone made a terrible mistake and she landed this gig. Visually it's flat and boring, looking like television. It misjudges its shock moments and is liable to do sequences of: (a) lame non-shock, (b) This Is A Shock music. It gives us cheap scares, but not enough good ones. Then you've got the throwaway ending, which is staged in such a distant, perfunctory way that the most surprising thing about it is the fact that it's followed by the end credits.
There's even a plot problem. You've got the Ju-on ghosts predicting that someone will commit murder in the future, which: (a) then gives that character plot immunity and you stop being scared, and (b) doesn't happen. I'm sure I'm mistaken on point b, but all I saw was the guy losing it and burying something that may or may not have been evil, possessed and/or already dead. Emotional weight? No, not particularly.
That's enough kicking. I dislike all those aspects of the film, but there's also enough occasional good stuff here that I can't simply call the film rubbish and forget about it. Some of the shocks work, even little ones like the moment at the beginning when the girl hits the window, while the banging is memorably nasty. I like the shabbiness of the hospital. Most importantly though there are a few scenes (usually based around the little girl) where the film suddenly gets really good, specifically the hypnosis and the exorcism. I also liked the ghost apologising to the sister, which isn't a Ju-on-like moment but felt almost poignant.
This isn't an obviously terrible film. It'll probably strike most people as being just more J-horror, a bit disjointed in its story and not particularly memorable. However it's frustrating because there's no reason why it couldn't have been a million times better than it is, had it been given a competent director and actors who could act. I'm not normally very good at noticing direction, but Mari Asato's work here is worthless. She's bringing almost nothing. It's the worst Japanese Ju-on movie, albeit better than the ending of the American Grudge 2. Not "nuke me" horrible, but it's only sporadically offering anything to its audience.