The movement is marked "Adagio, rubato, cantabile," and comprises a total of 16 measures, each consisting a varied number of beats ranging from three to twenty, with barlines marking only phrase divisions. It begins with two pairs of pizzicato chords separated by a glissando, an extended technique which was championed by Bartók.
[10] The pitches in the first chord pair constitute a D dorian scale, while the second pair has tonal implications, emphasizing the dominant and establishing the feeling of D as tonic. A melody in D phrygian begins. In an article delving into the technical aspects of the Sonata, Søren Beech suggests that the melody may have been inspired by ancient modal tunes preserved through the Eastern European folk music tradition.
[11] The modal melody is presented throughout the movement with distinct alterations: it is stated with rhythmic augmentation and then in polyphony, a testament to Ligeti's counterpoint training under Ferenc Farkas. A second melody is introduced in measure 6, this one with tonal implications, which are later confirmed by chordal accompaniment.
[12] Beech also makes the observation that the important tones of both melodies outline descending tetrachords, evidence of the influence of Bartók, who often used fourths as a structural element in melodies.
[13] After a final restatement of the phrygian melody in polyphony, the movement ends with a restatement of the opening pizzicato glissando motif arriving finally on a Picardy third.