How long did you spend getting to know the sheng before writing the concerto?

The sheng — or, to be more exact, its Korean counterpart, the saenghwang — is an instrument that has intrigued me since my childhood. But “Su” absolutely couldn’t have been written before I met Wu Wei. He is a pioneer par excellence, not only because of his expertise in the most different musical styles, but also because he has radically modernized the instrument’s technical properties, and continues to do so all the time. At present, he is the only person who can play this piece at all.

The first time I heard “Su,” I didn’t know the sheng. When the solo part started to involve brittle, edgy sounds, I thought perhaps you were using electronic modification. But the liner notes confirmed it was acoustic.

Yes, the tonal versatility and variety of the sheng is a source of marvel for me. I spent lots of time coming to grips with this very complex instrument. But the actual writing of the piece took relatively little time, curiously much less than the work on one of my piano études.

This piece, as well as others from the same period, like “Rocana,” sound like you are leaving behind some of the influence of the 20th-century European avant-garde.

That’s right. In my younger years, up to 40, I was very interested in the musical language of [the influential modernist German music institute] Darmstadt’s avant-garde. But as a composer, you get a little bit older — and perhaps a little bit wiser. So you are searching for new possibilities.