A 12 CD limited edition of 555 copies, Merzbient comprises recordings made by Masamik Akita (aka Merzbow) between 1987 and 1990. During this period, Merzbow was establishing himself as an early mover of the burgeoning Japanese noise scene, but these recordings were made in secret, with a combination of electronics and huge, non-portable hybrid acoustic instruments, including a giant metal box with piano wires, which he played with a violin bow. These recordings lay dormant and forgotten for years, until Merzbow rediscovered them and decided to issue them, in what is ostensibly a compendium of the lighter, quieter, gentler side of Merzbow, as suggested by the cover artwork, featuring lilacs hanging from a trellis, blue skies and a pleasant walkway through a botanical garden.

Don't be deceived. Merzbient is not ambient. Erik Satie, probably the first composer to expound on the idea of ambient, or "furniture", had in mind a music that was designed for the background, to be heard between the clank and clutter of cutlery at the dining table. Merzbient, by contrast, demands, and rewards, complete attention and absorption. For the very best results, book time off work. Eat in advance. Close the curtains. Remove all distractions. Perhaps even clear the room of all furniture.

Some of these recordings bear in their title the letters 'RBA', standing for 'Right Brain Audile', a term Merzbow invoked on Music For Bondage 2, which he also recorded about this time. But Merzbient can easily be taken in isolation from the rest of his frighteningly prodigious output. Although the sonic terrain covered here is vast, there is a methodological consistency to the gigabyte or so of sculpted noise that constitutes Merzbient. At times it reminds of the early recordings of AMM, whose scrupulously logical, fiercely cerebral collective effort to escape the earthbound confines of musical convention resulted in a sound that felt like levitation at times – there are similar, unbound, anti-gravitational moments here, as on 'RBA 1A'. There are sparer passages, as on 'Metal/4ch', with its quieter, serrated peals and rasping, mottled, metallic broadsides. Then there is 'Violinsolo89', a thing of luminous, wiry, blissfully scalding beauty despite making Tony Conrad sound like Nigel Kennedy.

It's tempting, given its 80s electronic means, its brutal collisions of metal and wire, its reverberant drones and atonal blasts to describe Merzbient in (post) industrial terms, to wax about welding sparks, towering girders, rusting hulks and turbines and the like. But Merzbow invites us to contemplate this music in a different way. Back to the cover art. Place together the 12 CD slips of Merzbient and they form a whole, an image of a Japanese garden. I'm reminded of Derek Bailey's comment that he regarded Improv as like a jigsaw – the end result was a banal, kitschy, dispensable picture, of little interest – what counted was the putting of it together, which is why he advocated the throwing away of his CDs once heard. Merzbient, however, is suggesting something else with his jigsaw, that's nothing to do with sarcasm or kitsch. He's implying that this "ambient" music, despite its disregard for conventional colour, melody and warm, balmy tones is akin to nature as nature is actually configured – think of the leaves and their twisted veins, rough bark, knotted roots, thorns, predatory insect life, rotting mulch, all of which are essential to make up that pretty, bucolic tableau. Embrace Merzbient as "natural", succumb to its remorseless, surrounding logic and, while this is hardly "escapist" music you'll find it hard to escape from it once deeply immersed.