Perhaps watching a woman having her ribcage torn apart or seeing someone drilling into a man's temples is not your idea of fun - but then again, if you are a male between 16 and 24 it may well be. If so, you will be looking forward to this week and the release of the sixth film in the notorious Saw series - once considered a niche concern, now a bona fide cinema phenomenon and the most successful horror movie franchise, outgunning Halloween, Nightmare on Elm Street and Friday the 13th.

The Saw films, which have been released every October since 2004, tend to excite mainstream critics to hyperbole, such is the contempt and indignation their graphic depictions of extreme violence provoke. The Los Angeles Times called the films ''vile filth'', The New York Times considered them ''a distasteful idea'', and the general view among grown-up commentators is that the Saw movies represent an artistic and moral black hole.

Not that those views have hindered the films at the box office; the combined takings for the five films is $US668 million ($748 million), and all went to No. 1 in box office charts all over the world. Saw's producers know their audience inside out; they give them exactly what they want and manage to entice them back to cinemas for another puddle of gore. It is easy to dismiss the achievement and to assume that the adolescent males who make up the biggest proportion of the Saw audience will always get off their backsides for taboo-breaking sex and violence, but the reality is more complex than that.

The first two Saw films occupied prestigious slots in the industry's collective consciousness. The first film, created by the Australians Leigh Whannell and James Wan on a budget of more than $1 million, premiered at the Sundance Film Festival in 2004, and the festival director, Geoffrey Gilmore, said the film was ''bold, cleverly constructed and flat-out terrifying'', and infused with ''moral seriousness''. Saw's premise - the terminal cancer sufferer Jigsaw, betrayed by a world in which the gift of life is undervalued, devises murderous games to test life-affronting offenders' right to survival - apparently marked it out from other, less thoughtful horror films and even inspired David Schwartz, curator of the New York Museum of the Moving Image, to pair Saw II with A Clockwork Orange in its 2007 horror retrospective.

Mark Burg, who financed the first Saw film and has produced all six, believes the film's audacity was appreciated by filmmakers and fans. ''I don't think any other producer in Los Angeles would make a movie whose main character is a serial killer with terminal cancer,'' says Burg, whose eclectic production roster includes Bull Durham and the TV comedy Two and a Half Men. ''We've always been true to our character. In every movie we ask questions we don't answer. We place clues that pay off later down the line for people who've stayed with the franchise.''

He adds: ''I'm glad I touched a nerve in the culture so well. There must be something that these audiences relate to. It's not just a bunch of scary traps.''

Ah yes, the traps. It is the frenzied interest - one might even call it a cult - around the increasingly inventive and gruesome traps that Jigsaw creates in the films that have elicited most concern among watchful guardians of the film world. Burg disputes the ''torture porn'' tag; he is not a fan of Hostel, another big-screen exponent of eyeball-popping sadism, and suggests it would be more appropriate if his films, superior in terms of characterisation and narrative, were compared to Silence of the Lambs or Seven.

But at the same time he is not averse to sending tantalising messages to fan sites promising that Saw VI will be ''a lot more violent'' than its predecessor. It is evident from a look at fan sites that the pre-Saw VI buzz is dominated by anticipation of how much more ''gross'' the next set of traps will be.

''It's a movie. We haven't killed anyone yet,'' Burg says.

''We make our films for our fans, not for the critics. I'm aware that Saw will never win an Academy Award, and we've come to terms with that.''

When pushed, Burg cites the importance of context in justifying the extreme violence in his films - Jigsaw is punishing those he regards as immoral, thus the torture is not presented with the sadistic glee manifest in the likes of Hostel. What is questionable, though, is how much kids care about context. The prevalence of YouTube montages made by fans that consist of torture scenes from the Saw films illustrates that, for some viewers, context is just an irritation to be got round, just like the establishing storyline in the Emmanuelle videos was for young boys in the 1980s.

''Is it wierd [sic] that I just got an erection after watching that?'' asks a fan posting on Facebook after viewing the brutal trailer for Saw VI. ''I wish it could turn my stomach, but some of the footage in the films are like stuff I do to my friends in my dreams!!!'' confides another on the social networking site Bebo.

The pioneering studies of the influential US behavioural specialist Dr Marvin Zuckerman suggest that a good percentage of horror fans are typical ''high sensation seekers'' - that is, males in their late teens who require increasingly intense ''hits''. No surprise, then, that they demand each new Saw delivers stronger thrills.

The stakes have already been raised for Saw VII; it will be in 3D.

Zygi Kamasa, chief executive of Lionsgate, which came in as co-producer with Burg's Twisted Pictures on Saw II, says: ''We're not forcing people to see these things.'' Would Lionsgate ever refuse to release a film on the grounds that it is morally irresponsible?

''Um … that's tricky. Our primary duty is to our shareholders to make money. Fortunately, there are safeguards … such as the [film classification board] that prohibit things. It's their duty, not ours.''

The studio does all it can to satisfy shareholders. For marketing it concentrates on drip-feeding teaser trailers and clips through social media and the official site. Perhaps the cleverest marketing move is the tagline that has accompanied the films since Saw III - ''If it's Halloween, it must be Saw.''

According to Kamasa, Lionsgate ''liked the marketing ploy that we owned that period in time every year. This is an annual event now. And I'll say, turning around a movie every year is not easy.''

Burg talks of three more films in the pipeline. When I ask if he hopes Saw VI will result in audience members fainting in cinemas, as they did for Saw III, he chuckles. ''Me?'' he says. ''I'm just keeping the medical profession busy.''

Guardian News & Media, via The Age

Saw VI opens on Thursday.
You can view the Saw VI movie trailer here on TheVine.