No. 1, Fantaisie pour la main gauche (Fantasy for the Left Hand), Largamente—Allegro vivace, A-flat major, 4/4 time

Befitting its title, “Fantaisie,” this piece is written in an improvisatory style using limited material. In terms of technique, it employs a wide variety of devices such as tremolos, octaves, chord leaps, and arpeggios, rather than relying on the repetition of specific figures, pursuing a symphonic sound. The entire piece is broadly divided into three sections by double bar lines, but from a formal perspective, it is largely divided into two parts at measure 93. The diagram below illustrates the formal divisions, measures, and key transitions of No. 1.

Part 1

It consists of a first half (measures 1–30) where two musical ideas (A and B) alternate, and a second half (measures 30–92) based on the development of A and B. Idea A consists of arpeggios and a melody reminiscent of a brass ensemble, extending from the low to the middle register.

The dotted rhythm in the uppermost voice in measure 2 is diminished in measure 6, and a transition to C major is formed by utilizing this rhythmic motif. C major is established by a perfect cadence in measures 11–12, and the tonic chord descends rapidly by five octaves and is struck, leading to B.

Idea B, presented in A-flat major, combines a melody in the middle register with a tremolo in the bass. From the mid-1830s, pianist-composers such as Chopin and Thalberg began to entrust rich vocal expression to the middle register. This was because the development of piano mechanisms allowed for sustained, expansive sounds from the strings in the middle register. This is why Alkan chose the middle register for the melodic theme of B (a similar example can be seen in Op. 14-1). While he could have surrounded the middle-register melody with arpeggios, following Thalberg's method, Alkan avoided his approach. B forms a balanced phrase of 8 measures (4 measures + 4 measures), and A and B return again, but this time appearing in F-flat major, each shortened to 4 measures (A1, B1), before returning to the tonic key. The subsequent return of A is further shortened, consisting of only 2 measures in D-flat major (A3). Using A3 as a transitional phrase, the development section enters a light 2/4 time, Allegro vivace. The development of A is divided into two parts: measures 30–46 and measures 46–61. In the first part, there is an alternation between the sextuplet arpeggios from the beginning of the piece and the descending melody of the fragmented theme (Musical Example 3). In the second part, the development proceeds with a new tremolo-like figure in sixteenth notes and octave chord leaps in eighth notes that conclude a phrase (Musical Example 4).

The development of B is shorter than that of A, consisting of a re-exposition of the theme in E-flat major and its variation through arpeggios (Musical Example 5).

In measure 74, the E-flat major theme shifts to G-flat major, and the arpeggios in sequence are given brilliance. The arpeggio arabesques move to C-flat major and A-flat minor, leading to the coda of Part 1. The codetta begins with the repetition of the motif that initiated A3, traversing the keyboard with sextuplets, and finally ascending five octaves in a single arpeggio, concluding the piece in E-flat major.

Part 2

Part 2 begins with a bass theme in A-flat minor, marked “Gravamente” (gravely/heavily), forming an 8-measure phrase with staccato notes like “tiptoeing” and a low-register trill placed at the end of the phrase (Musical Example 6).

Subsequently, a leisurely, march-like D appears in C-flat major, forming an 8-measure phrase. Here too, the melody is placed in the middle register (Musical Example 7).

From measure 109, the first variation of C begins. Here, the figure employs consistent repetition of a dotted rhythm. First, an 8-measure phrase in A-flat minor is formed by 4 measures + 4 measures, with the theme of C placed in the bass and harmonized above it (Musical Example 8).

From measure 120, the development of C1 begins. A figure, a transformation of the beginning of theme D, is presented with the same dotted rhythm (Musical Example 9), and from here it develops, modulating to E-flat major, G major, and so on.

C1’s development concludes with a C-flat major passage beginning in measure 126, and C2 begins from measure 132. C2, which begins with the tempo marking “vivamente” (lively), is a variation of C in the tonic key and represents a technical climax. The theme is consistently placed in the bass, while the hand holding octaves continuously leaps two octaves upwards within a single beat (Musical Example 10).

After presenting the 4-measure thematic phrase three times with varying textures, a new musical idea, E, is introduced. Here, a bass scale and a dotted rhythm in the middle-high register appear alternately, as if different orchestral parts are calling to each other (Musical Example 11). Furthermore, in this section, the rhythmic motif of C1 is utilized on the second beat.

In measure 150, the thematic motif of C (measure 97) is recalled, leading to a transition to a stretto (C3) in the tonic key. In the stretto, the theme is transposed to the major key and sung loftily at fff. However, after the initial four measures, when it appears a second time, chords from C major and F major are borrowed, adding color (measures 164–165). The coda, beginning in measure 170, concludes the piece at ffff, recalling the theme of B from Part 1.