Westerners don't tend to realise how influential Ringu really was. The highest-grossing horror film in Japan at 15.9 billion yen ($137.7 million), it was also voted the scariest and inspired the J-horror revival that brought us Pulse, The Grudge, Dark Water, Uzumaki and more. Like The Blair Witch Project, it seems to terrify even people who aren't normally scared of horror films.

Personally though, I never found it as frightening as everyone says. Ignore the hype, which never did anyone any good. Just put the film in your DVD player, turn down the lights and let it draw you into its world. This isn't a gore-laden, in-your-face horror film, but instead one that prefers just to hint at the truth and so force you to use your imagination. Take the victims' bodies, for instance. All the characters who see them are struck by the strangeness of how they must have died, but what's on screen wouldn't seem to justify that. The actors' mouths are wide open. That's it, really. Nevertheless it works, since this is a film that operates by suggestion and half-seen glimpses, forcing you to pay close attention in the hope of working out what's happening.

It's clever. It establishes its killer video as an urban legend, getting everyone talking so busily that we know all about it long before we've seen a single frame. Even that's scary. For there to be truth in a silly schoolgirl story is disquieting in itself. This approach also helps to justify the curse's arbitrary nature. Why seven days? Why not two, or even none at all? Why the telephone call? All these details are important to the film and it would have been damaging to remove any of them.

Then there's the technophobia, which I adore. It's wonderful! Thinking about it, too many horror films (especially American ones) don't scare you with anything recognisable but instead are just wheeling out monsters. Ringu's technophobia doesn't go as far as that of Ringu 2, but it's still a delicious idea to turn things like videos, telephones, cameras and even late-night TV into objects of terror. Furthermore, rooting itself so firmly in the modern world allows the characters to be intelligent and start analysing the video frame by frame. (Well, the intelligent thing would have been not to watch it in the first place, but that wasn't going to happen.) After that, our protagonists embark upon a proper investigation into what this thing is and how it came to be. It's all exactly what you'd want to be doing in their position. There's not an iota of idiot plotting here.

It's stylistically interesting too, almost documentary-style. They're certainly going for more realism than you'd expect and unlike the American remake, they avoid CGI shocks and cheap scares. There's almost no music, for a start. Much of the film is silent except for natural background noises which often do the job of incidental music. Birdsong. A typhoon. Crashing waves. Occasionally we get scary noises that I suppose I should be calling music, seemingly mixed up out of wind, bell chimes and odd discordant sounds. I think I heard scraping violins too.

Another documentary-style point is the different kinds of footage, such as low-quality VHS tapes or old silent films (albeit with sound) for the flashbacks to the experiment. That video footage is scary. I don't just mean the contents, although they're weird and disturbing, but all that VHS fuzziness. Brrr.

All that style is such an important part of the film that it got reproduced not only in the same director's Ringu 2 but also in Norio Tsuruta's Ringu 0. That's all good stuff.

There's also a footnote to this which incidentally ties into what I was talking about with silent cinema. The author Koji Suzuki based his novel Ringu on a Japanese folk tale, Banchou Sarayashiki, but furthermore drew on genuine history for the characters of Sadako and Shizuko. The real-life equivalent of Sadako was one Takahashi Sadako, while the real Shizuko was called Mifune Chizuko. Even the names are lifted. Chizuko was born in 1886 in Kumamoto Prefecture and said to be capable of foresight. She did a demonstration in 1910, much as Shizuko does in the film, but was denounced as a charlatan and killed herself with poison a year later. She and Chizuko weren't mother and daughter, but both were among the protegees of one Professor Fukurai, who was interested in ESP and the supernatural.

This 1998 movie could never have set its original events as far back as 1910, but might presenting them in a style reminiscent of silent movies have been a tip of the hat to the truth behind the fiction? Maybe. I'm speculating here.

I should mention the characters. The lead actress, Nanako Matsushima as Asakawa Reiko, is pretty but is doing that stupid high-pitched voice you'll sometimes hear from Japanese women. I've heard worse, but it's still distracting in the early scenes. Meanwhile her character's ex-husband, Ryuji Takayama, is exactly the kind of person you'd want beside you in a situation like this. He's rough, especially in his language, but practical and intelligent. He also has a beard. Japanese men look sinister with beards.

One thing I liked was that this is a film in which the two leads are an attractive divorced couple trying to save both their son and their own lives, yet you're never expected to start wondering whether or not they'll get back together. They understand each other and co-operate well. They're good together. However the untrustworthy-looking Ryuji is clearly fooling around with one of his students at the university and neither he nor his ex-wife ever shows the slightest interest in matters below the belt. They have more important things to worry about.

It's true but insufficient to say that Ringu is a ghost story. It probably feels stranger to us because we don't recognise the conventions of traditional Japanese ghost stories. More importantly, though, it takes ages for the film to give away even that much. The oogie-boogie stays out of sight. As always, the monster itself is less scary than it is to tiptoe around the edges of it. The spectres are introduced so subtly that you could almost miss them. A reflection in a TV screen. (That's a real "is that what I thought it was?" moment.) The words of a child. However at the end of the day, despite everything our protagonists find in Izu, it doesn't really matter why the curse works. The important thing is that it does and it'll kill you.

I'd always thought this was a well-made film, but I liked it even more after seeing its sequels. It stands up well to rewatching, although as I was never terrified out of my wits in the first place I can't comment on how having seen the sequels affected its scariness. No one could deny that it's atmospheric, but there's something about Ringu that can reach out of the screen and grab of your imagination. I know of someone who having seen the Clive Barker film cannot be persuaded to say "Candyman" three times near a mirror. I think Ringu works on the same level. Even the ending, while theoretically offering a get-out, is in fact so horrible that it's scary in itself. Why choose him of all people? Given that Reiko's a devoted mother doing all this for the sake of her son, I don't want to know what that says about parenthood.

Ringu might be the most important Japanese horror film yet made. I don't know enough about the field to be able to say for sure, but it's certainly the most important of its decade. For goodness sake don't watch it expecting The Most Frightening Film Of All Time, but simply surrender to it and let your imagination go to work. If nothing else, it might stop your children watching late-night television.