The magic number 7

The magic number 7

There is one sharp in the diatonic scale of G. There are six flats in the diatonic scale of Gb. The number of sharps in G and flats in Gb adds to 7.

An easy way to remember your diatonic scales is by deduction. For each letter, the number of sharps and flats adds to seven.

#‘s	0	1	2	3	4	5	6	7
D’scale	C	G	D	A	E	B	F#	C#
D’scale	Cb	Gb	Db	Ab	Eb	Bb	F	C
b‘s	7	6	5	4	3	2	1	0

Flat to natural to sharp

In the diatonic scale of G the only note to be sharp is F#. In the diatonic scale of Gb the only note to be natural is F.

G:	G	A	B	C	D	E	F#	G
Gb:	Gb	Ab	Bb	Cb	Db	Eb	F	Gb

This makes sense. Deduce Gb by lowering the notes in G a semitone. Now raise the notes in G a semitone. Natural notes change to sharp, sharp notes change to double sharp. That is why G# does not exist as a diatonic scale.

G#:

G#

A#

B#

C#

D#

E#

Fx

G#

C, C# and Cb all exist as diatonic scales. C is made of all natural notes. Natural notes can be raised a semitone without resorting to double sharps and lowered a semitone without resorting to double flats.

Patterns in the sharp notes

F# is very common.

Every diatonic scale with a sharp in it has an F# in it.

B# is rare.

C# is the only diatonic scale with B# in it.

D’scale	#‘s
G:	F#
D:	F#	C#
A:	F#	C#	G#
E:	F#	C#	G#	D#
B:	F#	C#	G#	D#	A#
F#:	F#	C#	G#	D#	A#	E#
C#:	F#	C#	G#	D#	A#	E#	B#

Sharp notes enter in order through the diatonic scales. The note F# is in every diatonic scale with a sharp note. C# is in every diatonic scale with two or more sharps. G# is in every diatonic scale with three or more sharps. D# is in every diatonic scale with four or more sharps. A# is in every diatonic scale with five or more sharps. E# is in every diatonic scale with six or more sharps. B# is in only one diatonic scale, the diatonic scale of seven sharps.

Patterns in the flat notes

Flat notes also follow a pattern, the direct mirror of the order of entry of sharp notes. Bb is as common as F#. Fb is as rare as B#.

D’Scale	b‘s
F:							Bb
Bb:						Eb	Bb
Eb:					Ab	Eb	Bb
Ab:				Db	Ab	Eb	Bb
Db:			Gb	Db	Ab	Eb	Bb
Gb:		Cb	Gb	Db	Ab	Eb	Bb
Cb:	Fb	Cb	Gb	Db	Ab	Eb	Bb

Remember

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