A9 guitar chords

A - C# - E - G - B

Chord Theory

An A9 chord typically consists of five notes: A (root), C# (major third), E (perfect fifth), G (minor seventh), and B (ninth).

A Major Scale: A - B - C# - D - E - F# - G#
Chord: A ninth - written as A9
Formula: 1 - 3 - 5 - ♭7 - 9
Notes: A - C# - E - G - B

A9 - A ninth (1-3-5-b7-9)

Spelling: 1st(A), 3rd(C#), 5th(E), b7th(G), 9th(B)

Chart Legend

Numbered Circles: number inside circle indicates which finger to use
X: Don't play string
White Numbered Circles: Optional Notes
X on string with optional note: if you omit the note, don't play string
Unmarked strings: Play open
Barre Line: One finger holds down multiple strings
R: Root Note

TAB: Numbers represent frets - not finger positions
Blank Strings: Do not Play
0: play string open

1st

Written: x02423
Notes: x-A-E-B-C#-G

TAB
e |-3-|
B |-2-|
G |-4-|
D |-2-|
A |-0-|
E |---|

2nd

Written: x05455
Notes: x-A-G-B-E-A

TAB  
e |-5-|
B |-5-|
G |-4-|
D |-5-|
A |-0-|
E |---|

3rd

Written: x05657
Notes: x-A-G-C#-E-B

TAB  
e |-7-|
B |-5-|
G |-6-|
D |-5-|
A |-0-|
E |---|

↓ A9 Guitar Chords

Notes

This chord is a dominant 9th chord which is a dominant 7th chord with an added 9th. It is an extended chord which includes the dominant 7th in its structure.
If a chord with a symbol 9 is not preceded by the words major or maj, i.e., A9 as opposed to Amaj9, the 7th is always a dominant 7th (♭7).
9th chords imply the presence of the preceding 1st, 3rd, 5th, ♭7th, before the added 9th.
In the 2nd position chord, the 3rd is omitted... this is a particular voicing of the 9th chord where the third is omitted, and the 9th is played an octave lower... this could also be classed as a 7th suspended 2nd chord, in this case A7sus2. The chord formula is 1-2-5-♭7 = A-B-E-G (notes in the second position).
Standard keys using the A ninth chord: D/Bm.
Bm is the relative minor of D major which means both scales share the same notes. A9 (A - C# - E - G - B) utilizes notes belonging to the D Major & Bm Scale... D-E-F#-G-A-B-C#.

Interesting facts about A9 chords

Often used as dominant chords, meaning they create tension that wants to resolve to a consonant chord, usually the tonic (I) or a related chord like A major.
The ninth (B) is the most distinctive note in the chord. It adds a jazzy and colorful sound to the chord, making it more interesting than a standard dominant seventh (A7) chord.
Can be played in different inversions, which means that the order of the notes is rearranged. This can create different chord voicings and textures.
Can be used as substitutes for A7 chords in various musical contexts. This substitution can add more harmonic interest to a progression.
Frequently used in jazz and funk music due to their rich and sophisticated sound. They are often used in extended jazz chord progressions.
The ninth (B) often resolves up to the third (C#) in chord progressions. This movement creates smooth voice leading and a sense of resolution.
In funk and R&B music, A9 chords are often played with rhythmic variations, such as staccato or syncopated strumming patterns, to create a groovy feel.
They can be part of interesting chord progressions. For example, you might find them in sequences like A9 - D9 - Gmaj7 - Cmaj7, which can create a jazzy and sophisticated vibe.
A9 is just one example of an extended chord. Extended chords (7ths, 9ths, 11ths, 13ths) are commonly used in jazz and other genres to add complexity and color to chord progressions.