This is the 24th measure of Bach's Minuet in G major BWV Anh 116. What does the parenthesis mean? In the previous measure the D has a #, but it shouldn't carry over. Re this piece, I have seen 3 versions in this measure: #D, ♮D, and (#)D. Does the parenthesis here mean it's optional? (one version marked as "urtext" has the natural symbol ♮)
I have a Verlag urtext edition with
D♯ in m. 23 and
D♮ in m. 24 both are without parenthesis. (The natural is actually notated, even though it isn't necessary after the barline.) It has the comment in German da in A kein ♮, fraglich ob d2 oder dis2 and Google translates that to there is no ♮ in [Notenbuchlein fur Anna Magdalena Bach], questionable whether d2 or d♯2.
After a play through I think the accidentals and comment are clear.
The starting key is
G major and do the
D is natural in that key. After the double bar it modulates to
E minor where the
D takes a sharp to make the leading tone. The part in
E minor ends at beat one of m. 24. The next phrase starts with the
D♮ and an immediate return to
G major. The
D is natural to restore it to the key of
You should check for comments in the edition with the sharp in parenthesis to understand what it's supposed to mean. Otherwise I would stick to the urtext.
The IMSLP manuscript https://imslp.org/wiki/Special:ReverseLookup/475024 has no accidental on the note in question...
The rules for how long an accidental applied for were different in Bach's time, and not as precise as we have now.
There is therefore some doubt about whether the 'missing' sharp in the following bar would be understood by a contemporary reader, or whether it was an oversight; or indeed whether Bach meant a natural.
Editorial indications in modern publications are shown in a different style from markings in the source, so that the reader knows which is which, and can make their own decisions.