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C 9th chord on guitar (C9)
Also called or written C9 or C
C 9th is built from C, E, G, B♭ and D. This advanced barre shape at the 7th fret requires a strong index barre and a muted high e string.
How it is built
Formula 1, 3, 5, ♭7, 9
- Root positionC–E–G–B♭–DC98-7-8-7-8-×
- First inversionE–G–B♭–D–CC9/E0-1-0-0-1-0
- Second inversionG–B♭–D–C–EC9/G3-1-0-0-1-0
- Third inversionB♭–D–C–E–GC9/B♭×-1-0-0-1-0
- Fourth inversionD–C–E–G–B♭C9/D×-5-5-5-5-6
How do you play a C 9th chord on guitar?
C 9th is played at the 7th fret as 8 7 8 7 8 ×: barre your index finger across fret 7, middle finger on the low E string at fret 8, ring finger on the D string at fret 8 and pinky finger on the B string at fret 8. The high e string stays muted.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 8 | 2 | C (1) |
| 5 (A) | 7 | 1 (barre) | E (3) |
| 4 (D) | 8 | 3 | B♭ (♭7) |
| 3 (G) | 7 | 1 (barre) | D (2) |
| 2 (B) | 8 | 4 | G (5) |
| 1 (e) | muted | — | — |
AdvancedThe index barre must fret the A string and the G string cleanly while the pinky reaches fret 8 on the B string.
8th fret
C 9th is played at the 8th fret as 8 10 8 9 8 10: barre your index finger across fret 8, ring finger on the A string at fret 10, middle finger on the G string at fret 9 and pinky finger on the high e string at fret 10.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | 8 | 1 (barre) | C (1) |
| 5 (A) | 10 | 3 | G (5) |
| 4 (D) | 8 | 1 (barre) | B♭ (♭7) |
| 3 (G) | 9 | 2 | E (3) |
| 2 (B) | 8 | 1 (barre) | G (5) |
| 1 (e) | 10 | 4 | D (2) |
C9/E inversion · 0-1-0-0-1-0 — the easy shape, no barre
C 9th is played in open position as 0 1 0 0 1 0: index finger on the A string at fret 1 and middle finger on the B string at fret 1. The low E, D, G and high e strings ring open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | open | — | E (3) |
| 5 (A) | 1 | 1 | B♭ (♭7) |
| 4 (D) | open | — | D (2) |
| 3 (G) | open | — | G (5) |
| 2 (B) | 1 | 2 | C (1) |
| 1 (e) | open | — | E (3) |
C9/E inversion · 0-1-0-0-1-3
C 9th is played in open position as 0 1 0 0 1 3: index finger on the A string at fret 1, middle finger on the B string at fret 1 and ring finger on the high e string at fret 3. The low E, D and G strings ring open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | open | — | E (3) |
| 5 (A) | 1 | 1 | B♭ (♭7) |
| 4 (D) | open | — | D (2) |
| 3 (G) | open | — | G (5) |
| 2 (B) | 1 | 2 | C (1) |
| 1 (e) | 3 | 3 | G (5) |
C9/E inversion · 0-1-0-3-1-3
C 9th is played in open position as 0 1 0 3 1 3: index finger on the A string at fret 1, ring finger on the G string at fret 3, middle finger on the B string at fret 1 and pinky finger on the high e string at fret 3. The low E and D strings ring open.
Full note and interval breakdown
| String | Fret | Finger | Note |
|---|---|---|---|
| 6 (E) | open | — | E (3) |
| 5 (A) | 1 | 1 | B♭ (♭7) |
| 4 (D) | open | — | D (2) |
| 3 (G) | 3 | 3 | B♭ (♭7) |
| 2 (B) | 1 | 2 | C (1) |
| 1 (e) | 3 | 4 | G (5) |
Why it sounds like that
C 9th combines a C major triad (1, 3, 5) with a minor seventh and a major ninth: 1, 3, 5, ♭7, 9. The ♭7 B♭ and 9 D give it a dominant quality. Compare it with C 7th, which lacks the ninth.
What goes wrong with C 9th?
- Letting the index barre collapse so the G string buzzes at fret 7.
- Allowing the high e string to ring open, which adds an unwanted E above the chord.
- Placing the ring finger on the G string instead of the D string, losing the fifth.
When to use it
C 9th functions as the dominant in F major, appearing in progressions like F–B♭–C–F (I–IV–V–I). It suits blues, funk and jazz-rock. Compare it with C major to hear how the seventh and ninth add tension.
Changing to and from C 9th
- Move to B♭ 9th by sliding the shape down two frets to the 5th fret.
- Move to C♯ 9th by sliding the shape up one fret to the 8th fret.
Which voicing to use
The 7th fret and 8th fret voicings both have C in the bass, but the 8th fret version adds the ninth on top. The C9/E inversion places the third in the bass for a smoother sound.
Other C chords
Common questions
How is C 9th written?
C 9th is written as C9. The symbol C9 always means a dominant ninth chord with a minor seventh and a major ninth.
What is the difference between C 9th and C add 9?
C 9th includes the minor seventh B♭, while C add 9 is a C major triad with the ninth D added and no seventh. The add 9 sounds more consonant and less bluesy.
Why does the C9/E inversion have a different bass note?
The C9/E inversion places the third, E, in the bass instead of the root C. This creates a smoother stepwise bass line when moving between chords in F major.