On its brand-new debut album, Selektiv Hogst (Sofa), Japanese-Norwegian quintet Koboku Senju follows a calm through-line across turbulent free improvisation, finding austere and meditative beauty in a profusion of sonic details and textures that easily could've been dizzying. Tetuzi Akiyama (guitar) and Toshimaru Nakamura (no-input mixing board) provide what little noise and aggression there is in the music—the former kicks up some dissonance on the opening track, "Nedvekst (Om a Vokse Nedover)"—but generally they stop at suggesting violence, creating an atmosphere of portent and dread with high-frequency long tones and sparse, ringing guitar. The Norwegians—tubaist Martin Tacks and remarkable trumpet-sax duo Streifenjunko—are responsible for most of the activity, combining unpitched streams of breath, striated legato phrases, sputtery flatulence, terse melodic curlicues, percussive popping, and more. It all collides and overlaps into an interwoven whole, so that it's useless to try to identify foreground and background parts; the pleasure is in how the components fit together and morph en masse. Tacks told me via e-mail that a few of the album's seven tracks developed from simple prompts—"someone saying a word like death metal, funeral march, or techno before we started playing"—but of course nothing here sounds remotely like any of those genres. The performances are beguilingly rich and uncategorizable, and Selektiv Hogst is easily the best free-improv recording I've heard in years. Streifenjunko and Akiyama & Nakamura open; Brent Gutzeit spins. On Thursday at 8 PM at Enemy (1550 N. Milwaukee, third floor) members of Koboku Senju will improvise in various configurations with locals Frank Rosaly, Josh Abrams, Michael Hartman, Brent Gutzeit, Todd Carter, and Aaron Zarzutzki.