Around ten years ago, a group of four young directors began to cause quite a stir in Tokyo movie circles. Their apparently sudden arrival in the public eye seemed all the more dramatic when it became clear that between them they'd already directed way over 50 films, and the longest-serving amongst them, Hisayasu Sato, had been in the director's chair since 1985.

So how had they managed to remain hidden from the public view for so long? Easy - they worked in a side of the market completely closed off from public or critical recognition, one whose target audience generally doesn't like to shout out about what they've been watching, and even if they did, would barely have taken time to look at the names written on the credits anyway. The four directors, who arrived on the scene simultaneously under the collective banner The Four Devils, all began in the industry making softcore "pink" films.

For a short period in the mid-1990s, pink cinema became all the rage, finding a new and curious audience outside of its original men-only adult theatre circuit, where the films played in triple-bill programs that changed on a weekly basis. The first retrospective of the Four Devils work appeared in the Athenée Français Cultural Centre in Tokyo, and several of the directors also had their later work showcased in venues such as the sophisticated Eurospace cinema in Shibuya.

An entire previously hidden genre, one which made up almost half of Japanese film production, suddenly seemed to be something more tangible and less taboo. As it was brought to attention that mainstream directors such as Masayuki Suo (Shall We Dance?) and Yojiro Takita (Departures, When the Last Sword is Drawn), not to mention actors such as Ren Osugi and Naoto Takenaka, all got their breaks in this clandestine industry in the 1980s, pink came to be seen as a vital training ground for fledgling talent in a filmmaking climate that had downsized so much that none of the major studios were taking on apprentices anymore, as well as the perfect medium for new directors to make their own personal expressions about contemporary society.

Ten years down the line and how does the picture look now? Against all odds, there is still a market for large screen erotic cinema, though no one knows for sure just how much longer it will survive. As for the Four Devils, none of them really quite achieved the breakthrough into the mainstream that was expected. Toshiki Sato has maintained a balance of minor independent works such as Lunatic (1996) and Perfect Blue (2002) alongside his pink films over the past few years, though with his last two, Apartment Wife Going to the Class Reunion (Danchi no Okusan Dosokai ni Iku, 2004) and Cuffs (Tejo, 2003), this balance seems to have tipped back in favour of the latter. Hisayasu Sato temporarily broke out of the ghetto, making a number of higher budget V-cinema movies including the gore classic Naked Blood (1996), only to find himself in the wilderness for a few years when the production company went bust. He made a non-pink comeback with the Caterpillar section of the omnibus movie Rampo Noir (Ranpo Jigoku), starring Ryuhei Matsuda and Tadanobu Asano. And Kazuhiro Sano hasn't directed a film since 1997, though has kept up a regular acting career (though it has to be said, only within pink). He is the only one of the four never to have stepped up outside of the pink industry.

Which leaves Takashisa Zeze, undoubtedly the best known of the Four Devils, and also the one with the most successful track record in terms of "real" films behind him. However, unlike the previous generation of directors from the 80s or before who used this underground training ground as a springboard into the major studios, Zeze has periodically returned to the sex film industry, alternating indie productions such as Hysteric (2000) and Dog Star (2002) with more ambitious pink works such as Dirty Maria (1998) and Tokyo X Erotica (2001). After all, pink productions are often more independent than so-called "independent" productions. Zeze's recent pink films have been produced entirely by one company, Kokuei, whereas, to take but one example, Dog Star received its funding from around five different agencies, all of whom want their input into how the final cut turns out. One of the truisms of the movie industry is the bigger the budget, the less the degree of control the director has, a fact that is clearly visible from Zeze's least typical work and the only one for a major studio, Moon Child.

So though it may initially seem strange that a director would wish to go from such lavish big-budget works as Moon Child back into the world of pink program pictures, in terms of the overall control afforded to the director (not to mention the challenge of shooting a film on a tiny budget on a three-day shooting schedule, then editing it and getting it out into the cinemas all within a couple of months), it's a decision that makes some sense.

Though he also directed Yuda, a DV-shot erotic drama that screened at Eurospace late in the summer of 2004 as one of the four films in the Ero-Bancho series, it's been four years since Zeze's last work for pink audiences, Tokyo X Erotica, and a lot of water has since flowed under the bridge. As such, there was a lot of excited anticipation as to what his return to the field would be like, and I am happy to report, Zeze has fulfilled his high expectations: A Gap in the Skin is by far his finest work to date.

It has to be said, Zeze's films often do not deliver the standard thrills one might expect from a softcore program picture, and this is especially true of his recent work. The Four Devils didn't stand out from the rest of the crowd for nothing. Each of the four directors earned their names and their notoriety by attempting to express something more than mere sexual activity. With Zeze's films in particular, it is not always entirely clear what that something is.

The closest to A Gap in the Skin in his oeuvre so far is his 1997 film Raigyo, a film in which atmosphere very much prevails over narrative. Similarly, A Gap in the Skin keeps its dialogue down to a bare minimum, and its plotting is sufficiently oblique to stimulate multiple individual reactions and interpretations. It certainly had most of the people that filed out of the theatre after its first private screening scratching their heads, including many of the actors who appeared in it. This tantalising work's immediate impact hits you at gut level, leaving you grasping for a subtext at the same time as seducing you with its rare, potent beauty.

Like many other Zeze films, including Hysteric, it takes a real-life crime as its starting point and weaves its story from there. The film begins with two young figures, a boy and a girl, desperately fleeing through the countryside on a scooter, which skids off the road and leaves them writhing on a grassy bank. For the first time we see his hands are bound together, whilst she has broken loose from her bindings, the rope still hanging around her cuffs. They are both bruised and bleeding.

The pair communicate through spasmodic body movements and animalistic grunts. He in particular seems shell-shocked and withdrawn, and her attempts to reach through to him seem futile. We soon learn that the young man, Hidenori (Otani) has killed just his mother, though the details behind the incident remain vague, and that the girl, Sunako (played by Fujiko, the lissom beauty who played the daughter in Miike's Visitor Q), contrary to her youthful appearance, is actually his aunt.

On the run, Sunako dreams of escaping overseas, whereas Hidenori repeatedly grunts that he wants to go home. After the two manage to hitch a ride in a passing ice-cream van, Sunako is assaulted by its driver while bathing in a stream in a forest. The two escape through the trees, eventually ending up in a secluded wooden cottage where they hide out, eking out a feral existence by raiding neighbouring gardens, gorging on stolen tomatoes and pumpkins. With Hidenori still in a state of shock, Sunako eventually breaks the communication barrier using her body, seducing him in a bathtub full of floating ripe tomatoes. It is a turning point in their relationship, with Hidenori now becoming the sexually dominant partner in this strange relationship. Then one day, Hidenori plunges a knife into his stomach, forcing the pair to leave their makeshift haven and seek help in the big city.

A Gap in the Skin has a slightly higher budget than is the standard for pink films, and it certainly shows in the visuals. The cinematography by Koichi Saito, the pink industry veteran who lensed most of Zeze's previous work, has resulted in a work that is just as beautiful, if not more so, than even the best of his previous collaborations with the director (for example, Raigyo).

Shot using natural light and entirely on location, the colour palette of strong, violent reds against lush, verdant greens - Sunako's scarlet coat making her figure stand out against the grassy backdrop - and the strong attention to textures - the camera focusing on the dried blood or water droplets on her skin - brings an invigoratingly tactile, almost hyper-realistic atmosphere to the film, heightened by the highly coloured sound design. So often the weakest link in pink films, where dialogue and all other aural effects are post-dubbed, here the all-pervasive backdrop of running water, wind rustling through the trees and doves cooing somewhere in their branches works in tandem to evoke all the primal energy of the natural environment.

Though a lot of Zeze's previous work has been known to turn people off with its slow, detached approach, this combination of sound and image is far more seductive, and besides, A Gap in the Skin is much more dramatically constructed than his previous work, with a higher usage of close-ups and medium long shots.

What any of it all means is anyone's guess. The closest comparison I could come up with is Korean director Kim Ki-Duk's The Isle (1999), another film where the mood and colour of the natural elements suffuses every frame, and another work where the meaning is left opaque enough to provoke hostile reactions for those trying to seek meaning in the chaos. And like the Korean film, it also features a fish-mashing scene the brutality of which is unlikely to endear the film to the censors, when Hidenori catches a trout from the nearby stream and bashes it into a bloody pulp using a rock.

But filled with such startling images as Sunako floating like Hamlet's Ophelia in a bathtub full of bobbing tomatoes as the sun streams through the window panes, A Gap in the Skin completely manages to transcend its pink origins, and could easily pass for arthouse fare in the same way that Kim's film did. Vivid, earthy, and undeniably erotic, there's no doubt it will eventually find an appreciative audience overseas. But god knows what the old guys in dirty raincoats are going to make of it.