A downloadable app will provide added effects and more on mobile screens during screenings of “Sadako 3D 2.”

TOKYO – Sadako 3D 2 will be shown in a “smartphone 4D” version in Japan, with a free app delivering vibration, flash and sound special effects as well as extra visuals on mobile handset screens for the latest installment of horror series The Ring.

Instead of the usual warning to switch phones off before screenings, audiences will be asked to keep them turned on to experience what the company promoting the film says will be the world's first-ever smartphone 4D effects. Full details of the effects are not being released, but there are hints that the app may also become active outside of screenings, and users may get calls from the ghostly Sadako herself.

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In the first Ringu (1998), victims in the movie received mysterious phone calls after watching a cursed video, sentencing them to die in seven days. A character became trapped in a smartphone in last year’s Sadako 3D.

“The 4D smartphone application is still in development, but it will include flashes, sounds, vibrations and things appearing on the smartphone screen,” Yasunori Minomata of No Future, the company handling promotion for the film in Japan, told The Hollywood Reporter.

Sadako 3D was given a theatrical release in Russia and South Korea, but whether the smartphone 4D system will be deployed for overseas screenings of the sequel has yet to be decided, according to Minomata.

Directed by Tsutomu Hanabusa, Sadako 3D 2 -- set five years after Sadako 3D -- stars Miori Takimoto as a clinical psychologist raising her four-year-old niece, whose mother died in childbirth. The cursed online video clip reappears, and strange things begin to occur around the young girl.

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The original Ringu, made for a little more than $1 million in five weeks by Hideo Nakata, went on to gross well over $100 million and kick-started the J-Horror wave that saw two U.S. remakes, the second of which Nakata directed.

Sadako 3D 2 is slated for an Aug. 30 release by Kadokawa Pictures in Japan.

Twitter: @GavinJBlair