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 |