Whether you think Boris exploits the devotion of their fanbase by putting out release after release or that they’re simply a vibrant, prolific rock band that’s trying to make their audience happy, you can’t blame the Japanese trio for at least trying to keep things interesting. It’s gotten to the point now, 14 years after the release of the seminal Absolutego, that we simply have no idea what to expect from them next. Two years removed from their excellent studio full-length Smile, there’s been no shortage of new material, ranging from double live albums, vinyl re-releases, and the quirky Japanese heavy Rock Hits seven-inch series, but still, for the casual listener it feels like the band has slowed down somewhat as of late, with none of their post-Smile miscellany really worth writing home about. When the band announced a musical partnership this past spring that nobody could have predicted, however, that buzz that Boris has always been so good at creating had returned.

As good as Boris’ proper albums are, their collaborations are always just as intriguing, and sometimes just as good as their original material. 2006’s Altar project with doom/drone lords Sunn O))) held up as well as anything either band had put out prior. Their albums with psychedelic rock guitarist Muchio Kurihara have been very worthwhile as well, most notably 2007’s gorgeous Rainbow. As appropriate those collaborations were, though, nobody could have foreseen BXI, their new four-song EP recorded with Ian Astbury. That’s right, that Ian Astbury, the powerhouse vocalist from ‘80s rockers the Cult and recent Jim Morrison impersonator with the Doors of the 21st Century. Juxtaposing such a classic rock ‘n’ roll vocalist with a style of music that never seems to lend itself well to bombastic, overtly theatrical singing would seem an awkward fit, but there’s no denying it would be great fun to hear how BXI would turn out.

In some respects the EP is pretty much as advertised: Ian Astbury singing over slow, sludgy arrangements, but what is surprising is how much of a factor Astbury is, and how underwhelming Boris seems. If Boris isn’t phoning in their performance, their sound sure is decidedly dialed-down. “Teeth and Claws”, for instance, is a no-frills exercise in shoegaze, guitarist Wata underscoring her soaring leads with simple, palm-muted riffs, drummer Atsuo hammering the living daylights out of his kit, as if trying to channel John Bonham. Compared to anything off Smile or any of their previous releases, this is painfully rote stuff, but that’s where Astbury’s presence comes in. He’s a master of rock melodrama, and he single-handedly transforms an ordinary song into something surprisingly affecting, bringing a level of passion to a genre that often relies on detached singing rather than raw emotion.

Less successful is “We Are Witches”, primarily because Astbury isn’t given much to work with, as Wata’s metal-oriented, down-tuned riffing isn’t very catchy at all. The subdued “Magickal Child” is a marginal improvement, as Boris gives Astbury a little more space to do what he does best, but again, the melody just isn’t there like it is on “Teeth and Claws”. Ironically, the best song on BXI is the only song without Astbury, the cover of the Cult’s great 1985 single “Rain”. It’s a fairly straightforward reading of the song, but the trio cranks up the psychedelia, Wata adding layers of searing guitars over her heavy rhythm riff while bassist Takeshi adds a massive, hyper-distorted bassline. Wata’s lead vocals, meanwhile, are far more akin to Can’s Damo Suzuki than Astbury’s, as she sings in a blissed-out, almost demure voice, her plaintive delivery giving the song a much more playful feel than anyone could have imagined. It’s the one instance on the record where it feels like Boris is actually showing some imagination, and it’s a shame they couldn’t sound as inspired with the formidable Astbury at the helm.

• Multiple songs MySpace
• "Teeth and Claws" MP3