This film is actually the third installment of the Ju-on series, and the first to get a wide theatrical release. It was preceded by two low budget films from 2000 known as (Ju-on: The Curse (2000) and Ju-on: The Curse 2 (2000)), whose storylines are continued in this sequel.
It would be easy to compare many similar scenes from the two movies, and though The Curse tops The Grudge in several individual scenes, it is superior in its pacing as well. At only seventy minutes long, The Curse is much tighter and makes for a more intense viewing experience.