This morning will feature the special and long-awaited premiere of Hilbert’s Hotel by the Dutch composer Rozalie Hirs, a spectral work in which the 31-tone organ is driven via laptop. This does not, however, mean that performing musicians will be absent from the concert. Guest musician Raymond Honing (flute/traverso) and the resident Fokker-organist Ere Lievonen will perform a striking 18th-century work by Charles Delusse, and later in the programme they will together perform Réflexions Sonores by the Dutch composer Henri Carf (1899–1984), a piece he composed in 1980 for flute and 31-tone organ. Additionally, Ere Lievonen will perform a tried-and-tested work based on Mozarabic music for the Fokker organ by Miranda Driessen. Later in the programme, a new 31-tone work by the French composer Charles van Hemelryck (b. 1981) will be presented, alongside a previously unperformed composition for flute by the Rotterdam-based violinist, composer, and microtonal thinker Leo de Vries (1924). As a prelude to King’s Day, which may already begin that evening, the programme will include the seven variations on “Willem van Nassau” KV 25 (1766) by Wolfgang Amadeus Mozart, performed, of course, in meantone tuning.