Mozart entered the Adagio for piano in B minor, K. 540, into his "List of All My Works" on March 19, 1788. It was composed between the Prague and Vienna premieres of Don Giovanni.
Mozart rarely used the key of B minor; his only other movement in this key is the Adagio from the Quartet for flute, violin, viola, and cello, K. 285, composed eleven years earlier. The key must have held special significance, for next to the entry in his personal catalogue Mozart wrote, "H moll" (B minor), the only time he ever listed the key of a work. Throughout this short piece, Mozart creates a tense, emotional atmosphere through the poignant use of suspensions and diminished sevenths.
Mozart's sense of symmetry and balance is everywhere evident in this highly dramatic but eerie and weary work. In sonata form, the piece opens by outlining a B minor triad; the rhythmically diverse theme continues through several dynamic changes. After an unexpected stop on the dominant, the theme begins again, but in the left hand, initiating the transition to D major (the relative major, a third above the tonic). The transition is brief, and the second theme consists of an ascending arpeggio, played forte, deep in the lower register of the piano, immediately balanced by a rising half step in the treble, played piano, after crossing the hands. Balance is again an issue in the development section, which starts with the main theme on G major (a third below the tonic), followed by the second theme, but inverted. Here, a descending arpeggio in the treble is answered by a rising half step in the bass. The recapitulation proceeds as we might expect, without the transitional passage. After a repeat of the entire development/recapitulation complex, a brief coda built of new material closes the piece in B major.
Mozart's Adagio has inspired numerous writers to wax poetic about musical meaning. Representative is Wilhelm Mohr, who in 1962 wrote, "Everyone who knows and loves the work agrees that in it the spirit of music has taken on form and sonority in one sublimely significant moment. One may try to get at it with analyses, but, however thoughtful they may be one realizes at the end of all effort that the true mystery begins only after them." ~ John Palmer, Rovi
