&dAInv. 9, BWV 780, r.h.&d@  

T = COMPOUND TURN-TRILL, m. 15: This mark appears to be the second 
"Doppelt-Cadence" of the "Explication", a turn followed by a 
trill.  The upward hook at the beginning is ambiguous, however -- 
it could be a hastily drawn vertical line, in which case this mark 
would be an "Accent und Trillo", an eighth-note appogiatura 
followed by a trill. The occurrence of sixteenth-note turns at 
analogous passages -- e.g. m. 4 and 32, r.h. -- seems to support 
the choice of a turn-trill, but the performer should experiment 
with both interpretations.
   m. 33: The distinct hook here shows this unambiguously to be 
a turn-trill.

N = MULTIPLE MORDENT, m. 15: Repeat the mordent several times; and 
this may include an anticipatory mordent, before the beat, or 
possibly one on the preceding B4 eighth to finish off the trill.
(See Neumann, p. 441.) 

J = COMPOUND SLIDE-TRILL, m. 16: The first "Doppelt-Cadence" of the 
"Explication", a trill preceded by a slide from the lower auxiliary 
up through the main note. A downward hook is at the start of a 
long-trill symbol.