# Schubert Impromptu - How do I notate these degree progressions?



## Gargamel

I find this piece (Impromptu No. 4, D899, Op. 90) an interesting one. The foremost conundrum for me is the unusual fact that it starts in Ab Minor, without bearing the key signature of Ab Minor. (The key signature is Ab Major!) In trying to decipher the chord progressions, I'm unsure whether I should designate the beginning as "i" or "I" (since the key signature is deceiving).

Measures 1-2 and 3-4 both move from "i" to V. I don't know why, but in measure 5 there is a minor 9th chord. Then there's the sentence structure which strikes me as odd. Feel free to comment.


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## EdwardBast

Yes, an interesting piece. 

Notating the beginning in Ab minor seems to be just a practical choice: The overall key is Ab major and a varied version of the opening passage will soon sound in the major mode. When that happens it will be more familiar and readily readable if the beginning is notated on the flat side rather than in G# minor, which is what one would do if the overall mode was minor. Starting on the sharp side would be pointlessly disorienting if one is going to change to flats on the second page. 

The chord in measure 5 is a dominant 9th chord, which I suppose is what you meant. The ninth is an essential feature of the theme, one which is preserved when the passage is repeated and varied in other keys and in the major mode as a major 9th.

If by the sentence structure you are referring to the six measure pattern, I don't find that peculiar.

As for Roman numeral analysis, you could just write Ab minor: I, V.

Or, if you'd rather analyze it in accordance with the key signature, you could write:

Ab: Ib, V, and later, Vb9 7 etc.


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## hammeredklavier

Gargamel said:


> The foremost conundrum for me is the unusual fact that it starts in Ab Minor, without bearing the key signature of Ab Minor.


Sure it is, but also do take a look at Beethoven Op.31 No.2 and Mozart K.243


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