I should know the answer to this, but I've forgotten it. In Bach or Baroque keyboard music should a trill begin with the note or above the note? I was playing the trill in mind starting on the written note, but now I'm not sure that is correct.

There are different kinds of trills. The mordant starts on the main note, but the prall (trillo) starts on the upper note (there are different thoughts about how to do the trillo when the upper note happens to be the same as the previous note, especially in quick tempo).

Bach's own ornament table he drew up for son W.F. should be your bible, see e.g.

http://members.aol.com/kjvisbest/jsb_ornm.htm

Thanks, Chris. I believe that a "regular" trill marked "tr with a long trill line" afterwards should begin on the note above the written note. I'll do it that way. I'm sure someone will mention it if it is incorrect.

I believe I remember how to execute mordants. I was taught to try to use three fingers to play a mordant...1-3-2, or 2-4-3, etc. It usually causes the third note of the mordant to sound accented. Correct me if that is not correct.

I am not sure if that falls under the same rule. It can also depend on the circumstances (the preceding
note).


I have no idea really. I tend to use the strongest fingers if possible because I have trouble with trills anyway, blaming it on the slow action of my grand. I don't think there is a hard rule here. Do whatever fits your fingers best (and sounds best).

Beside what was written here is also the question about the speed and the equality of the speed of a trill. My piano teacher now likes to have a baroque trill marked as "tr" played in equal speed. That means, not starting slow and/or ending slow and fast in between. Instead, equal speed and this speed is synchronized with the tempo. So normally played as equal 32th notes. That sounds very calm that way. That in opposite to the romantic manner - for Chopin she likes also to start the trill with upper note, but the speed played in a bow, starting slow, getting fast, ending slow.

Another point is when to start e.g. a mordant. I think for baroque music it should start with the beat and not before, so that the main note comes at the end of the mordant. That also in opposite to the romantic manner. Chopin did start that before the beat so that the main note comes to the beat.