Lesson on the circle of fifths

Many times when one refers to the Circle of Fifths we think of Scales. Today I would like to expose some secrets in the Circle of Fifths. Whether you are just beginning to play the piano or are an experienced musician, learning the theory behind the Circle of Fifths is an extremely important and valuable tool.

My understanding of the Circle of Fifths is that you must first be able to measure the interval of a perfect fifth. A perfect fifth encompasses five staff degrees and is made up of three whole steps and one half step, or seven half steps. Instead of counting steps, a perfect fifth can be more quickly calculated using information already learned in relation to the scale, the note from which the measurement will be made as the tonic. From a tonic note to its dominant note there is an ascending perfect fifth.

It is through the perfect fifth interval that the keys are related to each other. Starting with C, we count up to a perfect fifth to find the G keynote for the scale with a sharp; We count up a perfect fifth from G to find the D keynote for the scale with two sharps, and so on until we reach C# with seven sharps.

Flat keys are similarly related. Starting with C, we count back a perfect fifth to find the F keynote for the scale with a flat; We count back a perfect fifth from F to find the Bb keynote for the two-flat scale, and so on until we reach Cb, with seven flats. Each progression up fifths adds a new sharp, and each progression down fifths adds a new flat.

The code names used for 5, 6 and 7 sharps have enharmonic equivalents in the names of the keys of 5, 6 and 7 flats: B (5 sharps) and Cb (7 flats); F# (6 sharps) and Gb (6 flats); C# (7 sharps) and Db (5 flats). so now the circle of fifths in major keys is produced.

This circle includes all major key names with the high keys reading clockwise from C, and the flat keys reading counterclockwise from C. The circle is joined by the three enharmonic keys. The number of sharps or flats for each key can be determined by counting the number of fifths from C.

For example, A has three sharps because it is the third key clockwise from C; Db has 5 flats because it’s five keys counterclockwise from C. The circle also indicates the order of sharps and flats on the staff.