Mozart String Quartet in D Minor, K. 421 first movement
Element Measures Key/Mode Comments
Exposition 1-41 D minor with elements of A major reveals main melodic material
First Theme 1-14 D minor ends in HC
phrase a 1-4 D minor ends with IAC
The first section of this string quartet is play book throughout the first 41 measures. This string quartet is in sonata form and the first 41 measures are fairly predictable as far as the generally accepted exposition form goes. The movement is in D minor and from this part of the sonata, the expected second key area is the relative major key which is III of the D minor, or F major. Mozart does indeed modulate the key to A in measure 24 with the PAC consisting of the F major triad. Not only do the first few themes differ in key but they also have a drastically different feel mainly accentuated by the rhythmic acceleration that occurs between the two phrases. The second key area adopts a faster less stable sound that is driven my quick moving sixteenth notes. This is different from the slower first key area that has a driving bass of mainly staccato eighth notes. The character of the first movement of the first movement is slower and coupled with the minor key it gives the feelign of mourning, sadness and grief. As the movement speeds up however and shifts into the new key with the faster rhythms, it carries a lighter more playful and fun mood that is easily distinguishable from the first key area. The closing theme is much more accurately called a codetta because it branches from the original key material and elongates the cadence in preparation for the next section of music. The repeating notes in the Viola 2 and the arpeggios in the viola serve to elongate this cadence.
Measures 70 - 117 feature the recapitulation section of the piece as the tonal key is reintroduced and elements of the original theme are re expressed. The elements presented in the exposition including the two tonal areas are reintroduced in the recapitulation yet this time, the entire recapitulation remains in the key of tonic or D minor. This means that the light hearted bouncy section of the second tonal area is played this time around in D minor removing a lot of the cheeriness of the exposition and expanding upon the sadness and somberness of the piece. The movement ends in a somewhat humorous way as the virtuosity of the orchestral parts and the piano are kind of laughed at as the piece ends in a simple abrupt quarter note value chord that surprisingly ends the piece. Although there is definite buildup to the final cadence it is quite surprising.
The development section found in mm. 41 - 70 in comparison with the nature of the previous sections is not tonally stable by any means. There is no definite cadence or anything resembling such and the general feel of the section is of lost abandonment or a search for home, however sad it may be, through some, if any means. Although it is unstable, this movement consists of melodic material taken from previous movements including the original phrase found at the beginning of the first tonal area in the exposition. Although there are hints of key shifts to the III it generally stays in the D minor register with scattered chords in the III. If performing this piece I would adapt the second tonal area as the focal point because I believe it fleshes out the somber mood of the piece and represents the fleeting joy when it is reintroduced in a minor key, as if the only happiness the audience was looking for again was sucked in by all of the other somber sections and there was nothing left. i would therefore cherish the introduction of the III second tonal area of the exposition and accentuate the rhythms throughout the piece to help the audience get a crisp feel of the emotions. In addition a huge part of this piece are the dynamics which help set the mood.