The piece
Mozart finished his Piano Concerto No. 21 in Vienna in March 1785 and played it himself the very next day, at a concert given for his own benefit. In the middle, the Andante unfolds a long song over calm triplets; the Swedish film Elvira Madigan, in 1967, made it famous all over the world. When the piano comes in, Mozart gives it the theme the orchestra has just played: that page, his own piano part, is what you play here, as Carl Reinecke's edition (1862) prints it.
The left hand holds its bass and repeats its chords in triplets, gently, never hurrying: it is the carpet the melody sings on. The right hand plays the theme smoothly joined and lets the long notes breathe; in bars 8 to 11 it goes down low to answer itself, then comes back up. The held E of bar 12 carries a trill: play it first as a simple held note.
