W. A. Mozart: String Quartet in D minor, K. 421, First Movement: Allegro

Part C. of MTGW
Exposition: m. 1-41
First Tonal Area: m. 1-14, key of i, D minor
Phrase a: m. 1-4, HC in key of i with A6
Phrase a’: m. 5-8, PAC in key of i with D minor triad
Phrase b: m. 9-10, HC in key of i with A major triad
Phrase b’: m.. 11-14, HC in key of i with A major triad

Independent Transition to Second Tonal Area: m. 15-24

Second Tonal Area: third beat of m. 24-35, key of III, F major (Typical key change)
Phrase c: m. 25-28, PAC in key of III, F major triad
Phrase c’: m. 29-32, PAC in key of III, F major triad
Closing material for previous phrase, extension of cadence: third beat of m. 32-35, PAC in key of III, F major triad
Phrase d: third beat of m. 35-37, PAC in key of III, F major triad
Phrase d’: third beat of m. 37-39, PAC in key of III, F major triad
Closing Theme, Coda: third beat of m. 39-41

Exposition Notes

W. A. Mozart’s String Quartet in D minor, K. 421 is in sonata form. A typical key change a major key sonata form piece would go to in the exposition is the key of III, the relative major, and Mozart does indeed take the piece to the relative major key of F major in m. 24 with the PAC in the key of III with an F major triad. There are significant differences between the two themes in the first tonal area. First, they differ significantly in rhythm; the first theme of the FTA is driven by a rather slow eighth note pulse (see violin 2 and viola part of m. 1-4, for example). The second theme of the FTA, however, is driven by quick sixteenth notes (see violin 2 and viola of m. 24-25, for example). Second, the moods of each theme differ significantly; The first theme’s D minor key along with its slower rhythm create a somewhat somber, gloomy, and heavier character to the theme. The second theme of the FTA has fast, light, sixteenth notes and is in the key of F major, which makes the second theme lighter hearted, joyful, and playful in mood.

I believe the closing material of m. 39-41 is better labeled as a codetta since the joyful, light mood of the closing material is reminiscent of the FTA’s second theme, and the triplet sixteenth rhythm have been experienced before in m. 29 and 31.

Part E. of MTGW
Development: m. 42-70Tonally unstable, continuous harmonic and melodic motion

The development and the exposition are clearly divided harmonically since the development begins with an E flat major chord, a chord quite distant from D minor and the relative major of D minor, F major. Some motives used in the development section include the use of the one the piece begins with in the melody of m. 1-4. The difference is that rather than starting in the minor key of D minor, the motif is first played with a major chord quality of E flat major in m. 42, the beginning the development section. Another motif in the development used that was previously used in the exposition is the five sixteenth note-eighth note motif of m. 39-41 in the exposition, for it is used much in the development from m. 59-69. Of particular note is m. 67-69, where this motif is passed and played from one instrument immediately following the other taking turns playing it. For example, in m. 67, the viola first plays the motif, then the violin 2 right after the viola finishes playing the motif, then the violin 1 follows suit, etc.

Part D. of MTGW
Recapitulation: m. 70-117
First Tonal Area 2: m. 70-second beat of m. 83
Phrase a: m. 70-73, HC in key of i with A6
Phrase a’: m 74-77, PAC in key of i with D minor triad
Phrase b: m. 78-79, HC in key of i with A major triad
Phrase b’: m. 80-second beat of m. 83. HC in key of i with A major triad

Independent Transition to Second Tonal Area 2: m. 84-93

Second Tonal Area 2: m. 94-105, key of i, D minor (Typical key of Recapitulation)
Phrase c’’: m. 94-first beat of m. 98
Phrase c’’’: third beat of m. 98-m.102
Closing material for previous phrase, extension of cadence: third beat of m. 102-105
Phrase d’’: m. 106-first beat of m. 108, PAC in key of i, D minor triad
Phrase d’’’: m. 108-110, PAC in key of i, D minor
Closing Theme, Coda: third beat of m.110-115, extended Coda compared to exposition

Coda of Piece: third beat of m. 115-117

Recapitulation Notes

The recapitulation is, as expected, repeated material from the exposition. A typical key relation of the FTA2 going to STA2 is to remain in the key of i, and Mozart keeps the whole recapitulation in D minor. Of course, Mozart needed to alter some sections to have the recapitulation remain in D minor, especially since the original FTA and STA change key from D minor to the relative major key of F major. For example, rather than using something like the first inversion V/III chord in the third beat of m. 14, Mozart uses a startling C sharp fully diminished 7 chord for the recapitulation from the FTA2 to the STA2 in m. 83, which creates an unexpected shock to the listeners, yet still gives the listeners a sense of musically traveling since nothing like it has been experienced before in the piece. The most shocking difference between the first STA of the exposition and STA2 of the recapitulation is the key difference; STA is in F major, and STA2 is in D minor! The minor quality takes some of the joyful, light hearted charm of the F major STA away, creating a slightly more serious, somber mood than before, yet Mozart retains all of the motifs from the STA to STA2.

From a performance standpoint, the piece contains much musical value, as many pieces of Mozart do. The general feel of the piece is generally somber and gloomy, enshrouded by the D minor key quality set by the pace of the FTA of the exposition and the FTA2 of the recapitulation, among other sections such as the STA2 of the recapitulation and the serious, sudden forte ending in the coda of the piece in m. 116-117. This Mozart piece has some Beethoven qualities in it (including the darker mood of the piece), with sudden shifts in dynamics from forte to piano, and fortepianos and sforzandi marked in the score. The startling C sharp fully diminished 65 in m. 83 is an example of a chord shocking the audience in a Beethoven manner. The dynamics of the piece are a must to keep the spirit and shock of the piece alive, and other sections more expected of Mozart like the light hearted F major section of the STA in the exposition should be played as the mood is; light, and in a fun manner.