String Quartet No. 15 in D Minor

The second of Mozart’s string quartets dedicated to a highly appreciative Joseph Haydn, K. 421 was completed in the summer of 1783. If its formal planning doesn’t quite match the élan of its immediate predecessor, K. 387, emotionally it’s as complex as anything Mozart ventured in the key of D minor, including the Requiem, his opera Don Giovanni and the turbulent Piano Concerto No. 20, K466. The opening “Allegro” seems to hint at a painful subtext, but unexpectedly important is a little fanfare-like motif which is picked up by the “Andante” whose key of F major offers reassurance. Any consolation, however, comes under threat when tonal ambivalence invades the central section. From the “Andante” the motif relocates into a “Menuetto” once again ambivalent, this time thanks to the tension generated by a strong rhythmic profile which is besieged by melodic equivocation. Finally, the fanfare motif sounds a wake-up call in the theme which spawns the finale’s five robust, often unsettling variations—and slyly it bags the last word.