I'm looking for an explanation on the effect and reasoning of Bach's choices in the third measure of 'toccata and fugue in d minor'. I can only presume its a cadence to resolve the chord built in the end of the second measure (involving the c♯) but I do not know the names of the chords or what type of cadence this is. Does anyone know what Bach is doing here and why?
Measures two and three are:
Let's have a bit more context. We've got V7-I in D minor, three times. Then a prolonged C♯ dim7 over a D pedal, leading to a final Dm chord with the classic (or rather Baroque :-) sus4 decoration.
The C♯ dim7 has dominant function. Think of it as a rootless A7♭9 if you like. But it's over a tonic pedal. So we can look at it either as another perfect cadence, or as a massive multi-note appoggiatura delaying the final tonic.
Here's a completely different approach to analysing the piece (but I DO wish youngsters would stop calling everything a 'song'!) Read it for amusement, if nothing more. https://spark.parkland.edu/cgi/viewcontent.cgi?article=1118&context=ah
