Overview
Introduction
The Opus 90 impromptus consist of 4 typical Romantic-era pieces, each with distinct elements. The name Impromptus was given by the publisher.
No. 1 in C minor
The first Impromptu, written in C minor, is a set of variations on two themes. It commences with two widely spaced G octaves, leaving the key of the piece ambiguous. The piece continues into a march-like melody played first without accompaniment. The melody is repeated with a chordal accompaniment. (At the end of this statement the key is revealed: after a rising bass, the C minor chord is played in root position.) The march theme is embellished, then leads slowly into the key of A-flat major, where an apparently new melody is introduced. This melody is actually based on the opening melody: the first three notes are spread out more in their intervals but the following three repeated notes remain. Its lyrical quality, accompanied by triplets in the bass, contrasts with the march quality of the opening. An extension of this melody takes the final turn and repeats it several times in different registers. When the main theme returns for the first time, it has combined with the triplet pattern of the previous section. Later a new pattern with straight (non-triplet) semiquavers is used as accompaniment, modulating to G minor and then an off-beat version asserts itself in quavers. This theme is based on the second theme, and therefore leads into the extension of the second theme again, this time in G major, using the end of the theme's tonic chord as an effective dominant chord transition into the main theme. The theme gradually dies away and leads to C major, resolving the piece's tension into tranquility. This is the longest impromptu in this set.
No. 2 in E-flat major
Set in E-flat major, the piece begins with a lively scale-based and often chromatic melody in triplets; it is in compound ternary form (the A section is in ternary form itself). The middle subsection of the A section is in E-flat minor and is naturally darker than the opening though still very lyrical. The section ends with two oscillating figures which act as an important bridge both here and later. The first subsection repeats but moves quickly into a codetta which reasserts E-flat minor and the darker feeling of the middle subsection. A quick ascending scale leads to the B section in B minor (which however contrasting, is based rhythmically on the implied accents in the structure of the A section (123123123123)). This section is based on a figure alternating a widely spaced bare octave and an offbeat accented triplet. The alternation of octave and triplet becomes closer towards the end and the oscillating figures played at the end of the E-flat minor section return to lead back into the opening A section of the work. The Coda is a modified version of the B section, starting in B minor but alternating that key with E-flat minor, in which key the work ends. It is one of few single-movement pieces that begin in a major key and end in the parallel minor (another example being the Rhapsody in E-flat major from Brahms's Four Pieces for Piano, Op. 119).
No. 3 in G-flat major
This serenade is a classic example of Schubert's outstanding lyrical facility, as well as his penchant for long melodic lines. There is little interruption in the fluttering harp-like broken triad accompaniment, creating a tense contrast with the spacious and languid melody—an anticipation of Felix Mendelssohn's Songs Without Words. Without repeats, the melody develops into a shadowy and frequently modulating middle section before returning to its relaxed flow. Though written in G-flat major and 4
2 meter, the work was printed by the first publisher, almost 30 years later, in G major and 4
4 meter. The original version is now generally preferred.
No. 4 in A-flat major
The fourth Impromptu, in A-flat major, actually begins in A-flat minor, though this is written as A-flat major with accidentals. The opening theme consists of cascading arpeggios followed by murmuring chordal responses. These are repeated and developed, going through C-flat major and B minor before finally reaching A-flat major. There is a subordinate theme, accompanied by the arpeggio figure, varied with triplets. In the central section, in C-sharp minor, the arpeggios are replaced by a chordal accompaniment. This section ventures into the major mode towards its conclusion, but reverts to the minor. The opening section is repeated and the work ends in A-flat major. The tempo marking is Allegretto.
