Eight notes alternating half steps and whole steps, beginning with a half step. Because the pattern has a period of three semitones there are only three distinct forms, and any form contains the notes of a diminished seventh chord.
1 = A
b2 = Bb
b3 = C
3 = C#
#4 = D#
5 = E
6 = F#
b7 = G
Root
A
Scale
Diminished (half-whole)
Type
symmetric
Notes
A Bb C C# D# E F# G
Notes in the scale
8
Degree formula
1 b2 b3 3 #4 5 6 b7
Semitones from the root
0 1 3 4 6 7 9 10
Step pattern
H W H W H W H W
Aliases
Octatonic H-W, Half-whole diminished
Key signature of this root
A major / F# minor · F# C# G#
Written use
Named 1 b2 b3 3 #4 5 6 b7. The usual scale over an unaltered dominant seventh chord, especially one that resolves to a minor chord.
Notes and degrees
Each degree of the scale, its note name in this key, and its distance from the root in semitones.
Degree
Note
Semitones
Interval from the root
1
A
0
Perfect unison
tonic
b2
Bb
1
Minor second
b3
C
3
Minor third
3
C#
4
Major third
#4
D#
6
Tritone
5
E
7
Perfect fifth
6
F#
9
Major sixth
b7
G
10
Minor seventh
Positions on the guitar
The five windows below are computed, not copied from a shape chart. The script locates the lowest
occurrence of A on each of the five upper strings within the first twelve frets and takes a
five-fret window centred on it. Because a scale repeats every twelve frets, these five windows cover
the whole neck; the same sequence returns an octave higher. The positions are numbered from the lowest
fret upwards, so position 1 is always the window nearest the nut and position 5 the window nearest the
twelfth fret.
Position 1 — frets 0–2
Root on the 5th string A2 at fret 0. 12 notes of the scale inside this window.
Read the grid as a chord diagram: the top row is the first string. Degrees appear in the
notes and degrees table above; a filled cell is a note of the scale, and the shaded cell is the tonic.