In its original form, the koto is a 13-stringed zither-like instrument, associated with the delicately romantic music of traditional Japanese culture. Alongside other contemporary practitioners such as the American musician, Miya Masaoka, Japanese koto player Michiyo Yagi has, since the 1990s, done much to expand the palette and scope of the instrument, while liberating it from its courtly role and bringing it into the realm of free improvisation. Here, she plays electric 21-string and 17-string bass kotos, summoning an array of fleeting sounds in her dense extemporisations – from underwater harp and electrified church bells to Spanish guitar, wonky banjo and miniature toy piano. On Angular Mass, she's backed by two uncompromising Norwegian musicians – drummer Paal Nilssen-Love and noisician Lasse Marhaug – providing lightning flickers of brush on snare and misty electronic obfuscation. If the Norwegians seem uncharacteristically restrained here, they're even more polite and attentive on Soul Stream, which adds American free-jazz veteran Joe McPhee to the mix. While the snickers and windy whinnies McPhee produces from pocket trumpet slot neatly into the somewhat brittle sound world, his voice on saxophone has a transformative effect: always deeply human and tentatively lyrical, McPhee effortlessly encourages the group to transcend mere scrabblings and reach for the eternal.