semicord

G9 G dominant ninth chord

Notes
G B D F A
Formula
1 3 5 b7 9
Semitones
0 4 7 10 14 above the root
Other symbols
Gdom9

G to B is a major third (4 semitones), B to D is a minor third (3 semitones), D to F is a minor third (3 semitones), F to A is a major third (4 semitones). A dominant seventh (G7) with the ninth, A, on top. Guitarists usually leave out the fifth, D; the chord still reads as G9 while the third B and seventh F are there.

G9 on the piano

C4D4E4F4G4A4B4C5D5E5F5G5A5B5C#4Eb4F#4Ab4Bb4C#5Eb5F#5Ab5Bb5C4GBC5DFA

Root position from G4: G4, B4, D5, F5, A5. Middle C is C4.

G9 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 G as its lowest note.

GGDDFFBBDDAA
E-shape barre, root on the E string at fret 3
3 5 3 4 3 5 (low E to high e)
Sounds G2 D3 F3 B3 D4 A4
9fr×GGBBFFAADD
A-shape, root on the A string at fret 10
x 10 9 10 10 10 (low E to high e)
Sounds G3 B3 F4 A4 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 G9

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.

PositionNotes, bass firstNamedListen
Root positionG B D F AG9
1st inversionB D F A GG9/B
2nd inversionD F A G BG9/D
3rd inversionF A G B DG9/F
4th inversionA G B D FG7/A (also read as G9/A)

Where G9 fits

G9 is V9 in C major. It resolves like G7. 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 B D F A are Bm7b5, which is why pianists who leave the root to the bass player grab that shape.