Grace note

I was wondering if anyone knows this or has an opinion on it:

In many baroque/classical style (keyboard) pieces, you will find this grace note in front of a run (see picture).

In this case, you would perform the second measure the same as the first measure, correct? So I wondered, why would you write it as measure 2, if you can also write it as measure 1? My answer would be, it is actually an ornament, embellishing the other note (B in the example). In that case I would argue that first of all, an accent is given to the B (in contrast to the first measure, in which all the notes would sound more or less equal), but I can't believe that being the sole reason to write it that way. So second of all, that you could even leave out the grace note. But that would contradict with some of the views on ornaments/embellishments as being essential to a song for melodic reasons (like Bach felt). And I've never heard that being done.

I thought this was the practice because composers were not allowed to write a dissonant on the first (or another strong) beat of a measure, to write it as embellishment they could circumvent that rule.

Jaap's explanation is the jist of it. Keep in mind that ornamentations were always *on the beat* until the romantic period when the grace note moved to being before the beat. Trills were also reversed. Prior to the Romantic period, trills always started on the *upper* note of the trill. Today, they always start on the bottom note. Does it make a big difference? Not really, but it is a subtle thing that composers should think about. If in doubt, specify.

The three "rules" utilized in that period were as follows, going off of what I was taught about performing this music:

1. Appoggiaturas are played on the beat, not before. (Note that this does NOT apply to passing appoggiaturas, however. Though since you aren't specifically referring to a descending third pattern, I'll avoid going into detail on that aspect.)

2. The duration of the appoggiatura is as notated, with the value being subtracted from the note immediately following.

3. If the note following is a dotted note, then the appoggiatura usually lasts two-thirds of the value of the note immediately following.

I know there is an exception for some leniency with regards to allowing the appoggiatura to retain a certain amount of improvisation to how it's played, but this is the general way this era is read. I don't recall anything about why it was done, so I'm thinking jrcramer has that reason. But to answer your initial question, yes, the two measures you have given us are performed the same way. Of course, JS Bach never really notated what his appoggiaturas meant...so we just have to go off the common practice.

Thanks guys!

And that was the word I was looking for: Appoggiaturas! I knew it was called that way, just couldn't remember.

Well, as Gixander said, there is -some- variation in how the appoggiatura is played. Your original point about accentuation was actually quite good - except that you'd typically accentuate the appogiatura -itself- somewhat. In your first example, not the B would be accentuated, but the C, if anything at all. Sometimes, this accentuation is done dynamically, but sometimes also rhythmically, by making the duration somewhat longer. So contrary to what one might think, in the second bar of the example in the OP, the C might actually be played a bit -longer- than in the first bar, especially in a slow tempo (think some lyrical Adagio movement, for example). This is similar to all kinds of suspensions, which traditionally have often been somewhat prolonged and accentuated for a more intense expressiveness (such as the typically baroque sighing motives).

In slow tempi, having a series of regular sixteenth or eighth notes "swing" a bit (i.e. using "notes inégales" by making the first note of two longer and the second shorter) is a frequent practice anyways, especially in French baroque music.