Why Learn the Circle of 5ths?
Wouldn’t it be helpful to know what notes are included in each major key? Or to look at your box of harmonicas and know what notes each one is tuned to, on every hole?
What we’re talking about is learning key signatures. Key signatures tell you which notes are natural, and which notes have sharps and flats.
There’s an organizing principle to help you learn this stuff: the Circle of 5ths, also known as the Circle of 4ths.
What are 5ths and 4ths?
5ths and 4ths are intervals: the distance between two notes. For example, if C is note 1, then alphabetically, G is note 5. They’re a 5th apart.
C D E F G 1 2 3 4 5
Likewise, if C is note 1, then F is note 4. They’re a 4th apart.
C D E F 1 2 3 4
Natural Notes, Sharps (#) and Flats (b)
There are seven natural notes: C D E F G A B
There are five sharp / flat notes:
F#/Gb
C#/Db
G#/Ab
D#/Eb
A#/Bb
The notes with sharps and flats each have two names. They can be named as a lower note name with a sharp, or as a higher note name with a flat.
We’re going to focus on sharps in this article.
Examples of Sharp Keys
The key of C has no sharps or flats.
C D E F G A B C
The key of G has 1 sharp: F#
G A B C D E F# G
The key of D has 2 sharps: F#, C#
D E F# G A B C# D
The key of A has 3 sharps: F#, C#, G#
A B C# D E F# G# A
The key of E has 4 sharps: F#, C#, G#, D#
E F# G# A B C# D# E
What’s the Pattern?
Key Names
Let’s start with the key names: C G D A E
From C to G is a fifth.
From G to D is a fifth.
From D to A is a fifth.
From A to E is a fifth.
The sharp keys are following the Circle of Fifths!
Sharps
Now let’s look at which notes have sharps: F#, C#, G#, D#
From F# to C# is a fifth.
From C# to G# is a fifth.
From G# to D# is a fifth.
The sharped notes are also following the Circle of Fifths!
Conclusion: Sharps
1. To learn the sharp keys, start with C and follow the Circle of 5ths.
2. Each new key will add one more sharp to the previous one’s key signature.
3. To learn which notes to sharp, start with F# and follow the Circle of 5ths.
Like to Memorize Stuff?
Circle of 5ths
C G D A E B F#/Gb C#/Db G#/Ab D#/Eb Bb F C
Sharp Notes
F# C# G# D# A# E#
Scales with Sharps
C D E F G A B C G A B C D E F# G D E F# G A B C# D A B C# D E F# G# A E F# G# A B C# D# E B C# D# E F# G# A# B F# G# A# B# C# D# E# F#