The Circle of 5ths — How It Works & What It’s For
The Circle of Keys; The Circle of 4ths; the circle of 5ths — are they the same or different? Of what use are they?
Understanding the circle of fifths (and thus, the circle of fourths) and how it applies to music can be challenging. It’s important to have a visual representation (mostly seen in the form of a wheel), which you can purchase at most music stores.
Perhaps the best reason to study the circle of 5ths is it makes sense mathematically on a number of different levels and thus it’s very helpful to anyone studying music and music theory. Most often using a circle to display the relationships of particular key signatures (both major and minor), one of the functions of the circle of fifths is a geometrical representation of these relationships. The key of C (no sharps or flats) is usually placed at the top of the circle and is followed, in order and clockwise by the keys of G, D, A, E, B, Gb/F# (overlapping at the bottom of the circle), then D, Ab, Eb, Bb, F, finally returning to C at the top of the wheel. This order (going clockwise from the top) is determined by the amount of sharps or flats in a particular key. It goes as follows: C (no sharps or flats), G (one sharp), D (two sharps), A (three sharps) and so on.
The circle of fifths also shows corresponding key signatures and each major key’s relative minor key. (On the inside of the circle, the minor keys are displayed and are marked as such.) For example, the relative minor for C is A minor. We know this because both the keys C and A minor have no sharps or flats. As another example, the key of E has C# minor as its relative minor (both use four sharps)
You can also use the circle of fifths to study scales. If you wish to see a fifth on piano (the fifth note of a scale), start at any key (both black and white) and count seven half-steps to the right. That note (key) will be the fifth of the note you on which you began. Looking at the circle of fifths in regard to scales, taking it slowly, the note D is the fifth note of the G scale, the note A is the fifth note of the D scale, and E is the fifth note of an A scale, and so on.
The circle of fifths is also an effective way to show the relationships of the twelve notes of the chromatic scale (think of a piano with its white and black keys with the chromatic scale made up of adjacent piano keys played in succession G,G#,A#,B . . .).
Reading the circle of fifths as descending pitches going clockwise, or ascending counterclockwise, gives the circle of fourths. One can think about the circle of fourths as going in the opposite direction as the circle of fifths. Although circle of fifths is the more common term and is often used with the intent of describing both fourths and fifths.
For more details on the circle go to https://www.playpiano.com/101-tips/20-circle-of-keys.htm and also to https://www.playpiano.com/101-tips/21-circle-of-minor-keys.htm