I cannot for the life of me figure out what the form is in Mozart's Trio in B-flat Major K.502, in the first movement. The continuously repeated theme leads me to believe that it would be some type of rondo form (whether it be rondo/sonata-rondo, etc...), but from doing some research online there seems to be no concrete answer. Some websites are saying that it has concerto-like features, some are saying that it's a sonata form with a repeated theme, and it honestly brought me no closer to figuring out what the true form of this movement is. The second and third movements are fairly defined to me as rondo and sonata-rondo, but this first movement is really stumping me, and I could use some help/different persepctives on this matter.

I have no idea if this question is a bit too specific, but if anyone can provide their input it'd be greatly appreciated.

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    Mozart wrote whatever he felt like. He didn't care at all what the form was. Trying to retrospectively impose a form on his piece is futile.
    – PiedPiper
    Nov 14, 2020 at 21:51
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    if only I could write that on the test... Nov 14, 2020 at 22:00
  • the purpose of the test is probably not that you can say: this is a "rondo form" or wht ever it is. If you are able to discuss what features speak for a rondo form and which for a sonata or ay other mix form and find the right arguments you will succeed. Nov 14, 2020 at 22:30
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    unfortunately, the test is multiple-choice and fill in the blank, meaning that there is no room to explain my thoughts or have arguments or anything. it's simply "what is the form" and the teacher either marks it right or wrong. it's a cruddy way of doing things, because of the subjectivity of it all, but that's how the professor insists on doing it Nov 14, 2020 at 22:36
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    @PiedPiper I'm surprised you would trivialize Mozart like that. Form and balance were primary concerns in art throughout that time period — in music and in Mozart no less than any other art. Mozart's works are exemplars of the forms used at the time, and they are also exemplars of how composers pushed the boundaries or chose to stray from those forms.
    – Aaron
    Oct 13, 2022 at 4:51

2 Answers 2


The question is a good example of form being a matter of interpretation. For me, though, Mozart K502 is sonata form.

Sonata-form analysis

Measure references are to the Breitkopf Mozarts Werke, Serie XVII edition, and time references are to the Anne-Sophie Mutter/André Previn/Daniel Müller-Schott YouTube video (below).

Note: The video originally linked in this post is no longer available. The video currently included features the same recording, subtract 12 seconds from the timings below. Post will be updated fully when possible.


Presentation of first key area
mm. 1 - 12 / 0:12 - 0:32
Establishes Bb Major, ending with a brief cadence in Bb major before immediately moving on. The primary motivic material is introduced in bars 1-2: the first motif in the piano, and the second motif in the violin.

Transition #1
mm. 13 - 40 / 0:32 - 1:17
Kicking off with the primary motif in Bb major, Mozart quickly begins a tour through a series of keys using both the thematic material as well as flashy scalar passages, eventually landing in F major.

Presentation of second key area
mm. 41 - 48 / 1:17 - 1:30
Mozart now re-establishes the primary motivic material in F major, the dominant key to Bb Major. But only stays just long enough to establish the new key area.

Transition #2
mm. 49 - 68 / 1:30 - 2:02
Again beginning the transition with the main motif, Mozart also again tours through several keys, this time introducing arpeggiated passages along with more scale-work. The whole thing ends with the same sort of trill that would signal the end of a cadenza, arriving, finally back in F major.

mm. 69 - 82 / 2:02 - 2:26
This serves to firmly establish F major by way of an extended cadential passage. It differs from the transitional passages in that it hews closely to F major.

Repetition of exposition
2:26 - 4:42


mm. 83 - 97 / 4:42 - 5:11
A songlike, gentle departure from the previous material. Apparently Mozart wants us to appreciate the graceful beauty of F major.

mm. 98 - 117 / 5:12 - 5:45
Again kicking off a transition with main motivic material, but this time the second motif, Mozart winds his way back, in true retransition fashion, to the dominant chord of Bb.


First key area re-presented
mm. 118 - 127 / 5:45 - 6:02`
A more-or-less repetition of the opening of the piece, except leading us toward Eb major.

Transition #1: variant
mm. 127 - 155 / 6:03 - 6:46
This time Mozart kicks off the transition to the "second" key area in Eb major. This is necessary since his destination this time is different. In order to keep this transition similar to the parallel one in the exposition, it needs to be transposed.

Second key area material re-presented in first key area
mm. 156 - 163 / 6:47 - 6:59
A parallel statement of the exposition's presentation of the second key area, but now in the home key of Bb major.

Transition #2: variant
mm. 164 - 184 / 6:59 - 7:32
A modified Transition #2 from the exposition, this time providing transition from Bb back again to Bb for the coda, as opposed to the early F to coda in F transition. Note that again the "cadenza-ending trill" appears to signal the beginning of the end.

Final coda
mm. 185 - 198 / 7:32 - 7:58
A parallel passage to the coda of the exposition, firmly re-establishes Bb major for the final cadence.

Not a rondo

A rondo generally should have multiple repetitions of the primary theme in the primary key, with contrasting sections in between. In this piece, I don't find the primary theme substantial enough to stand on its own and does not have convincing enough contrasting sections. It also appears in too many different keys and contexts.

  • I wouldn't say it's a matter of interpretation. It's very clearly a sonata form with only one theme. If one didn't consider sonata forms with one theme to be sonata form, half of Haydn's sonata forms wouldn't be. Nov 15, 2020 at 4:13
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    Your analysis makes a great argument that this movement is one of those Mozart sonata-allegros where the recapitulation starts in the subdominant instead of the home key. (Mozart also uses this tactic in the 1st movement of his Piano Sonata No. 16 in C Major.)
    – Dekkadeci
    Nov 15, 2020 at 14:06

Having listened to it once, I would say it is in sonata form. The movement is clearly dominated by the initial motive but I can hear an exposition, development and recapitulation. Mozart just doesn't like to be too obvious or traditional, especially in mature works like this.

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