The album's core sound is a blend of Sakamoto's impressionist piano melodies and Nicolai's digitally processed beats and sounds. Released in 2005 by Nicolai's Raster-Noton label, it follows the duo's debut album Vrioon, which was named album of the year in 2004 by The Wire magazine.

Insen is heir to Vrioon (2003), Alva Noto's collaboration with Japanese multi-instrumentalist Ryuichi Sakamoto. Both represent something of a departure from the ascetic bent of their peers. Both explore the potential for interaction and tension between electronic and acoustic instrumentation, the latter taking form in Sakamoto's piano. This relationship lies at the core of Insen and continues Vrioon's cool melancholia in subtler, even more streamlined fashion. If each part of the marriage were isolated into constituent parts, they might prove too clinical or precious, but together a delicate vibrancy is created. The air-borne reverberations of the acoustic piano combine, impact and dissolve with digital loops, prods and waverings.

—Colin Buttimer, BBC^[4]

1. "Aurora" 8:52
2. "Morning" 5:27
3. "Logic Moon" 6:50
4. "Moon" 6:07
5. "Berlin" 6:17
6. "Iano" 6:53
7. "Avaol" 2:52

• Ryuichi Sakamoto – piano
• Alva Noto – electronics