On July 1, Philip Glass will join Dennis Russell Davies and Maki Namekawa on pianos as part of the German premiere of his Complete Etudes for Solo Piano. After premieres in London, Los Angeles, and Iceland. The touring activity for these pieces is picking up. This is good news considering that 16 of the 20 etudes were composed going on 20 years ago. The New York premiere of the complete set will take place in December at the Brooklyn Academy of Music with a huge roster of pianists joining the fun. Davies was commissioner of the first six piano etudes which coincided with Glass' desire to compose new piano pieces for himself to tour in the early-mid-90s.
Ruhr has been an interesting partner for Glass. In 2008, Davies and Namekawa performed the world premiere of "Four Movements for Two Pianos" and in 2013, Davies, Namekawa, and the Labeque sisters premiered "Two Movements for Four Pianos" (still unrecorded). But I believe this marks the first time Glass himself has performed at the festival.