- The Cast Showoff: Takako Fuji really can move like that, and has said in an interview that she sometimes likes to pull out her Kayako-moves to freak people out at parties. In addition, any scene with her crawling down the stairs was done without any wirework whatsoever.
- Irony as She Is Cast: According to Takeshi Shimizu, Yuya Ozeki, the cat-loving Toshio's best-known actor, apparently had a terrible fear of cats at the time of filming.
- Name's the Same: Confusingly, the original titles of the third and fourth movies are simply Ju-on and Ju-on 2... which are the exact same titles as the first two. The sub-titles The Curse (for the first two) and The Grudge (for the third and fourth) are usually added in foreign markets to differentiate between them.
- The Other Darrin: Toshio has been played by four actors in total throughout the entire Ju-on saga, including the short film 4444444444. In the aforementioned short, he was portrayed by Daiki Sawada. In the two V-Cinema films, he was portrayed by Ryōta Koyama, and in the two theatrical films, he was portrayed by Yuya Ozeki (who would then go on to reprise the role for the first installment of the remake series, as well as in flashbacks for the sequels). In Black Ghost and White Ghost, he is portrayed by Shūsei Uto.
- In Ju-on: Beginning of the End, Misaki Saisho has replaced Takako Fuji as Kayako, and Yasuhito Hida has replaced Takashi Matsuyama as Takeo.
- Recycled Script: Or rather recycled deaths. The last two films, The Beginning of the End and The Final (which are reboots) notably reused some of the death scenes and refitted them into the new setting, including:
- Yayoi's death is like Hitomi's from The Grudge (being pulled down into nothingness from under her bed), except that instead of Kayako, it's Toshio who killed her.
- Rina's death is like Izumi's from The Grudge (went mad, then pulled into nothingness into the cupboard). But courtesy of Toshio instead of Kayako.
- Aoi's death is like Kanna's from The Curse (her lower jaw being ripped). Again courtesy of Toshio instead of Kayako.
- Before Midori meets her demise, she sees her karaoke screen distort into something freakish and emit the rattling sounds. So just like Hitomi's back in The Grudge.
- Also, the whole plot where Takeo thinking that Toshio was not his son because he has a low sperm count was first present in the novels. Unlike the novels, though, Toshio really was not his son.
- There's one in the two reboots. If you notice closely, the entire third act of the two films are carbon-copies of each other ( Yui/Mai discover that their boyfriend (Naoto/Sota) has died from the curse, break down crying, then go to the house the next day to take revenge). Their endings are different, though.
- Sleeper Hit: The first two films.
Trivia / Ju-on