C9
C Dominant 9th — a dominant seventh widened with the ninth — fuller, funkier movement toward the resolution.
The keys
C – E – G – B♭ – D
What's inside C9
| Note | Interval from root | Degree |
|---|---|---|
| C | Root | 1 |
| E | Major 3rd | 3 |
| G | Perfect 5th | 5 |
| B♭ | Minor 7th | b7 |
| D | Major 9th | 9 |
A working voicing
Split the chord between two hands the way working players do — a solid shell low down, the colour tones up top:
| Hand | Keys |
|---|---|
| Left (shell) | C2 – B♭2 |
| Right (colour) | E4 – D5 |
Where C9 lives
As the I chord
C9 → F → G → C9
The classic I–IV–V–I motion with this chord as home.
In a ii–V–I
Dm7 → G7 → C9
The strongest cadence in harmony, resolving onto this chord.
Put C9 under your fingers
Hear every voicing, see the keys light up, and drill it in the interactive Chord & Voicing Lab.
Open the Chord & Voicing Lab →