It's my understanding that any accidental showing on the treble clef also applies to the bass clef unless indicated otherwise, correct?

For measure 13 of Chopin Nocturne Op. 9 No. 2, my Henle Verlag urtext (the image here is from a video but has the same notes as my Henle book) shows the natural sign for the note A in the treble clef, and no accidental shown in the bass clef. Shouldn't the left hand play the natural A, too? But I watched three videos and they all played Ab on left hand. (One video by Paul Barton used a score that has a flat sign next to the 2nd occurence of the A note in bass clef, but he played both A as Ab.)

Having said the above, I would tend to play Ab on left hand, too, since up to that part all the previous cases of the same chord combination had Ab. However, the Henle truly didn't have the flat symbol in the bass clef.

(Maybe it's no big deal? am I being too pedantic? ;-))

enter image description here


1 Answer 1


Accidentals apply only to the specific line or space on which they appear. For example, an A above the treble staff would also be an Ab unless specifically marked otherwise.

See Does an accidental apply to all octaves?.

  • Oh, thank you! I don't know how I got that mistaken impression! By the way, that Paul Barton played B-natural for the 2nd B on left hand (the bottom note of the blue arrow chord), which I think is wrong? Commented Feb 11 at 3:09
  • @GrandAdagio Based on the edition you posted, yes, Bb would be wrong. It's possible, however, that Barton simply chose to alter that pitch, because it gives a nice color to the harmony. Whether he's using a different edition, just decided on his own to make the change, or simply hit the wrong note I can't say, but I like the sound.
    – Aaron
    Commented Feb 11 at 3:14
  • 1
    @GrandAdagio Bar lines cancel any accidentals that appear in the preceding measure.
    – Aaron
    Commented Feb 11 at 3:28
  • 1
    Aaron, in this late version he corrected that: at 1:40 youtube.com/watch?v=O-0Gjl7oF5A Commented Feb 11 at 4:48
  • 1
    The rules are quite simple - accidentals (not key sigs) refer only to the notes that follow them, and they only last for the bar they're written in!
    – Tim
    Commented Feb 11 at 8:59

Not the answer you're looking for? Browse other questions tagged or ask your own question.