C9 C dominant ninth chord
- Notes
- C E G Bb D
- Formula
- 1 3 5 b7 9
- Semitones
- 0 4 7 10 14 above the root
- Other symbols
- Cdom9
C to E is a major third (4 semitones), E to G is a minor third (3 semitones), G to Bb is a minor third (3 semitones), Bb to D is a major third (4 semitones). A dominant seventh (C7) with the ninth, D, on top. Guitarists usually leave out the fifth, G; the chord still reads as C9 while the third E and seventh Bb are there.
C9 on the piano
Root position from C4: C4, E4, G4, Bb4, D5. Middle C is C4.
C9 on the guitar
Standard tuning (E A D G B E). Strings run low E on the left to high e on the right, frets downwards; × is a muted string, ○ an open string, and each dot shows the note it sounds, with the root in blue-green. Every shape below has C as its lowest note.
x 3 2 3 3 3 (low E to high e)
Sounds C3 E3 Bb3 D4 G4
8 10 8 9 8 10 (low E to high e)
Sounds C3 G3 Bb3 E4 G4 D5
The E-shape and A-shape grips are movable: an E-shape chord's root is the note under your first finger on the low E string, an A-shape chord's root is the note on the A string. Slide the same grip up or down to play dominant ninth chords on other roots.
Inversions of C9
An inversion puts a note other than the root in the bass. The name is what semicord's chord finder calls those notes played bottom to top; a slash name like C/E means a C chord with E in the bass.
| Position | Notes, bass first | Named | Listen |
|---|---|---|---|
| Root position | C E G Bb D | C9 | |
| 1st inversion | E G Bb D C | C9/E | |
| 2nd inversion | G Bb D C E | C9/G | |
| 3rd inversion | Bb D C E G | C9/Bb | |
| 4th inversion | D C E G Bb | C7/D (also read as C9/D) |
Where C9 fits
C9 is V9 in F major. It resolves like C7. In funk and blues it is also played as I9, IV9 and V9 of a twelve-bar blues, with no pull to resolve at all. Without the root, its upper four notes E G Bb D are Em7b5, which is why pianists who leave the root to the bass player grab that shape.