The opening concert of the festival, "Pētera Vaska kvartets // ARĒNA 2026", is a concert in Riga at the Riga Reformed Church on 27 October 2026. The line-up features the Pētera Vaska Quartet: Magdalēna Geka (violin), Egīls Šēfers (clarinet), Kristaps Bergs (cello), and Iveta Cālīte (piano). The programme includes Olivier Messiaen's "Quartet for the End of Time", Arvo Pärt's "Fratres", and Peteris Vasks' cycle "Episodi e canto perpetuo". This concert is part of the “ARĒNA” New Music Festival and marks the 80th anniversary of Peteris Vasks. The event offers an engaging chamber music selection in a historic Riga church.