I just started to learn the Trio movement of Mozart's K331. It sounds really nice but is the hardest movement of this piece for me. (By the way, why are the Menuetto and the Trio often counted together as one movement, sometimes just "Menuetto"?).

For the measure 11 of the Trio, my understanding is, E, A, G# with the left-stems are each 1/4 beat and should be held longer while E2-A, C#2-E, B-E, each note being 1/8 beat, are being played, respectively, am I right?

I'm asking because in the following two linked videos, both pianists released the 1/4 beat E, A, G# while holding the E2, C#2, B which are supposed to be only 1/8 beat. Are they both wrong or did I miss something?

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Video 1: @1:32

Video 2: @6:10

  • 4
    What is the “Trio” in a march? should answer your question about the Menuetto/Trio.
    – Aaron
    Commented Sep 4, 2023 at 4:43
  • 1
    In case it doesn't, the answer is that the Trio is part of the Minuet.
    – phoog
    Commented Sep 4, 2023 at 16:04

3 Answers 3


From measures 1 to the first beat (A) of measure 14 we hear 2 voices, a soprano+alto duet. If you play JUST the 2 voices to simulate singing, the phrases in each voice need to be connected as an implicit legato; sometimes it's quarter note duration (like in measures 1, 3, 5), sometimes it's 8th note duration (like in measures 2, 4, 6), but always together in duration separated by a 3rd or 6th interval.

The rest are fillers for harmonic, rhythmic movement, flourish, and cadence functions. For example:

  • the repeated 8th notes A in measures 1-2 are fillers for a sense of rhythmic movement
  • the doubling of the soprano voice in the upper register (ex. where the left hand crosses over in measures 4-5 including the cute grace notes in measure 9) are flourishes to add character
  • the notes in the bass clef are mostly cadence highlights (such as measures 3-4, 7-8, 11).

Mozart is creative in that in measure 10 he transposed the alto voice to the lower register while the usual 8th note rhythmic filler stops into the half note E to let the soprano and Alto have the focus as well as preparing us for the cadence in measure 11.

Within this passage context, it's then clear that we have to analyze measure 11 as follows:

  1. First voice (implicit quarter duration): E2, C#2, B which resolves to A in the next measure
  2. Second voice (implicit quarter duration): C# (in bass clef), A1, G#1 which also resolves to A in the next measure
  3. Cadence highlight: E in beats 2 and 3 in the bass clef, resolving to A in the next measure
  4. Rhythmic filler (off-beat 8th notes): A1, E1, E1

I think in measure 11 the alto is notated in quarter notes because the voices at this point have quarter duration, and Mozart (or the editor) helps us identify A1 and G#1 as the 2nd voice continuing the first beat C# in the bass clef. Since the character of the 2 voices in this passage moves together in duration as well as in melodic contour, the alto needs to be heard with the same duration as the soprano. Although in the notation there is a common beam for the 8th notes, it's very important to identify and to play the off-beat 8th notes A1, E1, and E1 as filler, not as part of the soprano.

A side note about the primacy of highlighting voices vs. actual notation

Highlighting the voices is more important than how long you actually hold the notes. In the first video we can hear a good rendition of the 2 voices performed according to the analysis above. Even though in measure 11 she plays the 2 voices about 1/8 duration, we hear it as a connected phrase (each note 1/4 duration). It's the effect that counts, after taking into account the room's acoustics and the decay curve of a note of a specific piano (remember, piano is by nature a percussive instrument), so pianists need to constantly adjust the actual length of holding the notes through feedback mechanism from what we hear.

This is especially true in Mozart's repeated notes (such as the left hand in the first few measures in Sonata Facile) where despite all are 8th notes, no artist would play those notes exactly the same duration. Otherwise, it will sound robotic as the "Play" button in MuseScore will demonstrate. I bet you that the MIDI duration values of Ms. Mitsuko Uchida's playing it will be very different for each note since she's holding the Cs and Ds much longer than the other 8th notes to highlight the bass line. The same goes for the right hand scale runs in measures 5 to 10 as Lang lang demonstrates various options we can play it.

  • Thanks for the explanation. So what if the score were written to reflect how it's played, i.e., making the E2, C#2, B quarter notes, and the E, A, G# eighth notes, maybe also changing the stem directions accordingly? Commented Sep 4, 2023 at 14:36
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    @GrandAdagio It's possible, but that's where interpretation comes in after considering many factors: notation convention and how Mozart would do it (compared to other composers from different period), the function of that voice line, and thirdly how it should be rendered because after all, what matters is beautiful sounding piece that preserves all the nuances the composer would have had in his mind. Commented Sep 4, 2023 at 15:21
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    @GrandAdagio Also to consider is that Mozart's fortepiano has a lot shorter decay than a 9' Steinway concert grand. So he MAY played it full duration quarter notes and he MAY meant that for fortepiano players in his time. But unless we play that in a fortepiano, we have to adjust the way we play to modern piano, and make MORE beautiful sound using the new potentialities. This is especially true when playing Bach's harpsichord pieces. Commented Sep 4, 2023 at 15:22
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    @GrandAdagio Here's Mozart's Sonata in A K.331 played on Mozart era instrument (fortepiano made by Silbermann) by fortepianist Mako Kodama, the Trio passage starts at minute 14:16, measure 11 at 14:30. Since fortepiano decays a lot faster and has less dynamic & tonal range, you can see how she has to play a lot more legato, hold the notes longer in general and fingers keeping close to the keys (like an organist). I cannot really tell how long she holds E2, C#2, and B, but I can clearly hear those are connected in a phrase as a subsidiary voice. Commented Sep 4, 2023 at 15:56
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    @GrandAdagio After I played the passage at the piano myself, it becomes clear that the passsage from the Trio is a duet. So I tweaked my answer accordingly. Commented Sep 4, 2023 at 17:03

In a comment on another answer, you ask

what if the score were written to reflect how it's played

Mozart could not have written the score to reflect how these two performers play the piece.

In the question, you ask

Are [these performers] both wrong?

There's no "right" or "wrong" here. The notation is the composer's means to communicate with the performer. These performers are playing instruments that use technology developed decades after Mozart. Some interpretation is necessary.

Piano scores do not generally dictate such minutiae as how much space to place between notes. You can always add a little more or less space; it is one of the parameters that pianists use to shape the phrasing. If there's some space between the notes then you can use the same finger on both. If you have to use the same finger on both, well, then, that will affect your phrasing choices.

If adding space between these notes bothers you, then by all means see if you can work out a way of playing the A with the 3rd finger and the G♯ with the second. Mozart may indeed have intended that. But the Firefly Piano video is elegant and graceful, and the alto voice has a definite presence and identity as a distinct voice; it's really a fine performance, certainly not "wrong." If you can learn how to achieve all of those things while also connecting the alto voice in a legato phrase, then by all means, go for it.

But keep in mind:

Daniel Gottlob Türk writing in his Clavierschule (1789) says that:

"...when notes are to be played in the usual manner, that is to say, neither staccato nor legato, the finger should be raised from the key a little earlier than the value of the note requires."

Source: https://www.dolmetsch.com/musictheory21.htm

I believe I've seen that an earlier treatise recommend holding "normal" notes for half their nominal value, as many modern writers recommend for staccato, but I can't find the reference just now. Anyway, Türk is contemporary with Mozart, so more relevant.

  • Thanks, points well taken. Now I begin to understand why I can't get that nice melody out as the Firefly pianist does (not just in this measure). Commented Sep 4, 2023 at 18:20

"What you're missing" is that the E-C#-B-A constitutes the melody, which is made clear by its immediate repetition an octave higher. This is implied earlier, in measures 3 and 4, when the upper notes of the "detached" eighth-note melody are repeat at the octave in quarter notes.

  • 4
    Could you please extend your answer and explain, why the fact that these notes constitute the melody implies that they (and the the accompanying notes) are not played as long as written in the score?
    – Arsak
    Commented Sep 4, 2023 at 6:56
  • @Arsak it's always permissible to insert spaces between notes in the name of phrasing. If it weren't, there'd be no need for legato markings. In fact, earlier in the 18th century you have treatises saying that by default every note should be held for half its nominal value.
    – phoog
    Commented Sep 4, 2023 at 16:11

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