The Grudge 2 teaser

"For The Grudge 2, I was going for this mystery that was never there in Grudge 1, and I think that's going to fulfill the audience. ... There's a secret about Kayako's childhood life, so that's part of the big mystery. And the other mystery is, this grudge will never stop, and it's going to ... spread. And how is it going to get spread? That's another mystery."

He then added... "The Grudge 1 was a complete remake of Ju-On 1, meaning the storyline was very similar. Basically, it's the same. But Grudge 2 is actually different from Ju-On 2, and I don't think I would have accepted this job if it was going to be [the] same storyline. And because it was a different story, you know, my motivation was a bit higher, and I actually enjoy doing this."

From Upcoming Horror Movies.