Some stories are so powerful they take on a life of their own. That's certainly the case with Kôji Suzuki's 1990 novel "Ringu" (The Ring).
Thirteen years after it was first published, this supernatural tale of ghosts, cursed videocassettes, and techno-horror has spread itself around the globe.
Maybe if Suzuki - the East's answer to Stephen King - knew what an impact his book was going to have, he might have had second thoughts about unleashing "Ringu" on his unsuspecting readership. Then again, considering how many yen he's collected in the process, maybe not.
Telling the story of a mysterious videotape that kills anyone who views it seven days afterwards, "Ringu" was first adapted as a Japanese TV movie in 1995. It proved so successful that a proper film deal was quickly arranged.
The movie, "Ringu", hit cinemas in 1998 on a double bill with a hastily made sequel, entitled "Rasen" (The Spiral).
Then things started to get really complicated, as "Ringu" copied and multiplied itself like one of the story's cursed video cassettes.
First a second sequel, confusingly entitled "Ringu 2", followed "Rasen". Then came another TV show.
Eager to cash in on "Ring" fever, a Korean film company released a pirate version of the story called "The Ring Virus" in 1999.
Then the new millennium brought a Japanese prequel, "Ringu 0: Baasudei" (Ring 0: Birthday) and a big budget Hollywood remake courtesy of Steven Spielberg's DreamWorks company.
So what is it that makes the Ring series so popular?
Part of the answer is nothing more than fortuitous timing. The 90s were a particularly difficult decade for Japan. As "Ringu" director Hideo Nakata points out: "We've seen some very violent or bad things happening in Japanese society, like the Aum Doomsday cult and the insurance killing incident where people killed themselves for money."
Hit by economic recession, the technology market crash, increasing unemployment and an apparently bleak future, Japan was more than ready for a ghost story that combined modern gadgetry (videocassettes, telephones) with urban myths.
The Hollywood remake, directed by Gore ("The Mexican") Verbinski and starring Naomi Watts and Martin Henderson, has proved equally popular. So successful, in fact, that it too will spawn a sequel.
Whether we'll see the same merchandising phenomenon as in Japan - which has produced everything from "Ringu" dolls to mobile phone accessories - will be revealed when the film opens in the UK. Just give it seven days.