I am practicing the number 1 Invention (BWv772).
This is my very first piece. I could not resist trying it.
My Yamaha P90 digital piano plays the first trill (in the first measure): b-a-b
(This made me play all trills in the same manner).
Now I see in this forum (and elsewhere) that this trill should be played. c-b-c-b instead.
Even if this i not as harmonic (?) as the mordent it makes the trill stand out better (?).
(Still another alternative would be a "turn": c-b-a-b)
So I will try to change at least some of my misunderstood-mordents to trills.
The first three is quite straight forward (at least I think so) and I have changed them.
Then to the fourth trill in measure 8. Trill on f#: g-f#-g-f#.
Before the trill I play the notes g-a-b-c-a-b-g with my fingers 1-2-3-4 (1=thumb)
that is: g(1)-a(2)-b(3)-c(4)-a(2)-b(3)-g(1)
So shall I trill with fingers 1-2 : g(1)-f#(2)-g(1)-f#(2) (quite hard)
or trill with fingers 3-2: g(3)-f#(2)-g(3)-f#(2) ( not so hard but do not fit with the other fingering so well)
or change everyting to what ?

Göran/Sweden.