Cadd9 is the C added 9 chord. Its notes are C, E, G and D. A major triad plus the ninth, without a seventh. Let the upper notes ring.
How to play Cadd9
Open shape
x32033
Open alternative
x32030
Barre chord
fret 3, A shape
x35753
Barre tip: the long bar marked BARRE means one finger presses several strings at once. Lay it flat just behind the fret, press with the bony outer edge rather than the soft middle, and keep your thumb behind the neck. Pick each string one at a time and nudge the finger until none of them buzz.
Numbers show frets from the low E string to the high e string; x means don't play that string.
What's in Cadd9
C1
E3
G5
D9
Formula
1 · 3 · 5 · 9
Also written
Cadd9, Cadd2
Chord type
Added 9
Cadd9 notes across the neck
Every C, E, G and D on the first 12 frets. The filled dots are the root, C. Build your own shape from any nearby group.