Circle of Fifths
Whether you're a classical pianist, a jazz saxophone player, a bassist in a rock band or a headlining DJ, the circle of fifths will help you write and understand music theory.
How to read the circle of fifths
The Circle of Fifths is a shortcut to understand key signatures and the relationships among chords. All of the major keys are arranged around the outside of the circle of fifths. Opposite them are their relative minor keys, which lie inside the circle. Since any major key and it's relative minor key use the same key signature (they share the same sharps and flats), the circle of fifths is an easy way to see all of the key signatures laid out.
The top of the circle is C major which has no sharps or flats in its key signature. Going clockwise from C we add one more sharp than the previous key. Each key starting with C adds one more flat than the previous key going counter-clockwise.
A fifth is defined as an interval which is the most consonant interval other than a perfect octave. Thus, the circle of fifths is essentially a collection of pitches arranged in a circle in which each pitch is 7 semitones (a perfect fifth) away from each neighboring pitch. This rule applies for the outside circle (the major keys) and the inside circle (the minor keys). The circle of fifths is designed as such to help musicians visualize these relationships.
History of the Circle of Fifths
How and by who, exactly, was the circle of fifths invented? This seemingly magical tool was developed by a Russian composer by the name of Nikolay Diletsky around 1670. He first referenced this development in his book Grammatika which acts as a guide to composition. Although the design has morphed over the years, its original form has pretty much remained the same since its inception almost 400 years ago.
Understanding the Circle of Fifths
Understanding how to read the circle of fifths will help you visualize the relationship between the major keys and their relative minor keys, one of the most fundamental and important relationships in music theory. Every major key has a relative minor and every minor key has a relative major. In both of these instances, the same key signature is used. In other words, a major key and relative minor key share the same sharps (#) and flats (b).
When you read the circle of fifths, you’ll see that there is both an outside ring and an inside ring. The outside ring consists of the 12 major keys while the inside ring consists of their 12 relative minor keys.
The top of the circle is the key of C major, which has no sharps or flats in its key signature. As mentioned earlier, going around the circle will either add one sharp or one flat depending on the direction you are traveling.