In the summer of 1917, Leoš Janáček met Kamila Stösslová, a young woman almost 40 years his junior. His passionate love for her remained platonic, but it inspired a number of works written over the following years—most notably the Second String Quartet of 1928, in which Janáček told the story of this relationship, entirely without words. In the first of its two Pierre Boulez Saal concerts this season, the Berlin Staatskapelle String Quartet performs this musical declaration of love, together with the composer’s First String Quartet, written in 1923. Actor Udo Samel, a longtime member of the ensembles at Berlin’s Schaubühne and Vienna’s Burgtheater, will read from Stösslová and Janáček’s numerous “intimate letters.”