Got the first two seasons on DVD I think. Enjoyed it, but I have no idea if they did more seasons than that. There was also at least one episode that wasn't shown on TV. It was directed by Takashi Miike, the guy who did Audition which if you've seen or heard about it should give you an idea why it wasn't broadcasted back when it was made.
Miike's segment was "too intense" for the show. (On Prime cable no less) I'm not kidding that was the reason they never actually aired it. Apparently, he made too horrific a horror episode for a show that features horror stories. Granted, it is intense. I am not sure If I can watch it again. Heck, Miike dives head long into horror. Yes, I have seen "Audition" It's intense. If you run across more than "Audition" do so. The man knows how to scare.
Oddly, he also knows how to make childrens movies. Mind you, what qualifies as a "Childrens movie" in Japan is not quite the same standards as the US.
BTW; they only produced the 2 seasons.