If Detonation! Violent Riders (Bakuhatsu! Boso zoku) isn’t the coolest-looking biker film, it’s close. Although it's fantastic shots of riders and an all-too-cool lead combine with an exploitative approach to sex and violence, that means it won’t be for everyone. At its core, 1975’s Detonation! Violent Riders is a riff on West Side Story, with the action and tragedy of rival biker gangs clashing given authenticity by real-life racer Kôichi Iwaki playing his namesake central character.

Iwaki is a mechanic who falls in love with the wrong girl, Michiko (Tomoko Ai), who, in turn, becomes an unfortunate pawn in a rivalry between two biker gangs. One is the Hell Dogs, a large gang with a leader emblazoned with a swastika haircut, and manipulated by Mitsuda (Yûsuke Natsu), a former gang leader Iwaki bested in a daredevil duel. The other is the Black Panthers, a gang that’s grown around him as its mysterious and reluctant leader. Iwaka doesn’t see himself as a biker but as a racer, though that doesn’t warm him to Michiko’s gruff, retired racer brother, Tsugami (Sonny Chiba). It’s only when Michiko is abducted that the pair form an uneasy alliance, and the violent clashes between the gangs finally detonate.

 Picking up on the contemporary issue of bikers that were dominating the news at the time, alongside strands of Iwaki’s biography, Detonation! Violent Riders continued Toei Tokyo’s reputation of courting controversy. There’s much in the studio’s infamous Yakuza films that carried over into this film, which was intended to kick off a Machine era of similar films. That didn’t pan out, with sequels failing to hit Violent Riders’ impressive box office the following year. It’s a shame, considering the powerful, sensationalist success of this film, that the plan didn’t stick, but then again, it packs in a lot, both memorable and disturbing.

 The film constantly returns to hectic shots of Tokyo's roads as the bikers weave through them, showing why director Teruo Ishii was one of Toei Tokyo’s favourites. It doesn’t hurt that Iwaki’s skills as a racer meant the editing didn’t have to contend with stunt drivers (something that didn’t hurt the budget either). Ishii is endlessly inventive in how he shows the bikes and their riders, including some fun little jump cuts to keep the streets and the screen full.

 It’s when the bikers arrive en masse that the film reaches an impressively chaotic onslaught. Real bikers were invited to take part in filming, adding to the bedlam from the first scene. The visual essay that accompanies this release references the inevitable results behind the scenes, including fights, accidents, and even kidnappings. But it looks incredible, backed by tremendous sound design and a constant, high-tempo funk track alongside the roar of engines.

 Roger Corman had helped chaperone the American biker craze into being with 1966’s The Wild Angels. Nine years later, Violent Riders showed Japanese cinema kept to the central tenets of this gas-guzzling stand of exploitation movies: fast bikes and punches thrown while the engines kept running. The violence isn’t too graphic—often relying on well-applied blood pellets—but it purrs under the film.

 Iwaki’s stoic leader of the pack faces several key tests, including taking the mantle and later dealing with the death of one of his youngest gang members. Earlier, Iwaki had shown the unfortunate kid that he could spare time for his mother. Later, a powerful and heartbreaking scene has the kid cry out for his mother.

 Other parts aren’t so delicate. Female characters are on the blunt end, sometimes shown as abusers just as bad as their male counterparts, but more usually undressed or caught in prolonged rape scenes. Morally, there are huge question marks on both sides of this turf war, despite Ishii’s evident efforts to bring humanity to the bikers. More palatable is the minor turn by Sonny (Shin'ichi) Chiba. Despite being at the peak of his powers, here he takes on the affecting role of a racer who gave up everything for his family. The mix of emotion, tonal shifts, violence and high drama means there’s never a dull moment on the way to an inevitably bleak ending.

 Special features on this colourful 88 Films release include a stills gallery, trailer and an audio commentary by Ashley Darrow and Jonathan Greenaway of the Horror Vanguard podcast. Also, a fast-paced video essay from Nathan Stuart, new to this release, which adds considerable historical and behind-the-scenes context for the production (even if it has distractingly popping audio).

 Surprisingly, the video essay skimps a bit on the film’s portrayal of women and sexual violence, with more emphasis on the direction Iwaki’s career subsequently took. However, it’s hard to argue with the point that this new release offers a great chance for Detonation! Violent Riders to reach a broader audience in the West.