I'm currently learning Bach's Prelude and Fugue in D Major, No. 5 WTC 2, BWV 874. At the beginning of the prelude, there are two time signatures given - cut time (2/2) and a 12/8 time signature.
I found another post on here that helped me understand parts of the timing for this prelude. For example, in certain measures, like mm. 1 and 3, the quavers are to be treated as "triplets" or can be counted in 12/8 time.
My immense confusion starts in Measure 5. A post I saw mentioned that the quaver-semiquaver figure in the left hand coincides with the third quaver from the quaver "triplet" (marked in the red boxes). It also looks like within the first semiquaver-quaver group, the semiquaver in the dotted quaver-semiquaver figure falls with the 3rd and 4th semiquavers that open the bar (marked in the blue boxes). I'm really not sure how the math works out here. This confusing pattern repeats throughout the prelude and I'm so lost.
Regardless of whether we treat the dotted quaver-semiquaver figure as triplets or as written in 2/2 time, should the semiquaver in the left hand be played after the third quaver from the quaver "triplet" in the right hand? Am I missing something or not understanding something here? Would appreciate any help!!