Attached is a picture of one of my piano students' Bach Inventions (BWV 785). What does the +- mean? I've never seen it used before. A precursory search online revealed nothing. Sometimes a + indicates a raised tone, and a - indicates a lowered tone. This is all I can think of but it doesn't make sense in this setting if that's it.
-
1I would bet there would be some explanation in whatever edition this came from.– RichardOct 4, 2018 at 18:10
-
1@Marzipanherz since that marking is editorial it's highly unlikely that it exists in any other edition.– phoogOct 6, 2018 at 3:57
-
1@Marzipanherz that's true, but my point is that the editorial markings express the editor's interpretational ideas, and the chance that another editor has had the same idea is probably rather small.– phoogOct 6, 2018 at 21:02
-
1@Marzipanherz I just edited to add the BWV number.– Kevin HOct 9, 2018 at 19:35
-
1Kevin H if I were you I would explain to the student that the markings have nothing to do with Bach and suggest getting an edition that doesn't have editorial expression markings. If you want to teach your student how to interpret such markings, use repertoire from a later period where the composer actually used them. Alternatively, you can help the student decide whether to agree with the editor's interpretation or to come up with his or her own.– phoogOct 9, 2018 at 20:22
2 Answers
I have seen + used to indicate an ornament, but I think this is an older sign from before Bach's time.
Also, the - could be tenuto.
But I don't think this is what they mean in this score. Try @Richard's advice and look for an explanation in the edition.
This isn't a direct answer, but it may be helpful...
According to IMSLP this is the measure from your question in Bach autograph...
...no ornaments.
And this...
...is a well known guide to ornaments also in Bach's actual writing.
Whatever those marks are supposed to mean they aren't Bach's. Same goes for the expression markings. It seems worth noting those things are someone else's additions and are not Bach's instructions.
I don't know this symbol, but I think it would probably be an indicator of either volume, as it is near that crescendo, or fingering. Some guitar sheet music will use + and - for position shifts (if you need to go up 3 frets with your 1st finger, +3 is indicated at that note). It could also be indicating a slight variation in tempo, as in specifying the rubato.