Phew. Here goes.
Overview of Mozart's 15th String Quartet in D minor, K. 421:
EXPOSITION (m. 1-41)
FTA - m. 1-8
- two four-measure phrases, IAC and PAC in i
transition - m. 9-24
- modulates to III with PAC in F major at m. 24
STA - m. 25-32
- two four-measure phrases, two PACs in III
KL (closing theme) - m. 33-41
- a series of PACs in III, followed by retransitional (the first time) or transitional (the second time) material in m. 41
DEVELOPMENT (m. 41-69)
- opens with development of FTA "octave + accompaniment" motive (originally found in m. 1, 5); developed starting in Eb major, the Neapolitan key to i, in m. 42-45
- goes on to develop another FTA motive, the "trill + chromatic neighbor" motive (originally found in m. 2, 6); developed in m. 46-49
- finally, develops motive from closing theme, the "arpeggio + staccato sixteenths" motive (originally found in m. 35, 37, 9-40); developed in m. 59-69
retransition - m. 66-69
- prolongation of A major (including long, held A (V) in cello in m. 67-69) announces return to FTA in m. 70
RECAPITULATION (m. 70-117)
FTA - m. 70-77
- remains relatively untouched, back to D minor (i)
transition - m. 78-93
- maintains same motives but does not modulate away from i
STA - m. 94-102
- mostly the same, except in i rather than III, and starts in the middle of m. 94, rather than at the beginning as in m. 25 - also, ends after downbeat of m. 102
KL - m. 102b-112
- mostly the same, except in D minor, with several PACs in i this time, including "arpeggio + staccato 16ths" motive from before. After 112, there is a repeat sign - so this may also serve as a transition, once again, for the development, or (as in the recording I heard, where they chose not to repeat the development) as a transition to the coda
Coda - m. 112-117
- basically just a typical cadential extension, lots of V - i, with the "arpeggio + staccato 16ths" motive used and partially developed once more, before the very end.
Additional notes and tying-up of loose ends:
The tonal areas (i - III, etc.) are fairly typical and well-tonicized.
I chose to label the KL as such because of the coda at the end, and because of the repeats - it isn't just a coda, and if it is, what does that make m. 112-117? An addenda? I don't think so.
Hope that's all. Good grief.
Good night all.