So in a previous lesson we started talking about the circle of fifths. We’re going to dig a bit deeper into that because there is a lot of information. To understand what it means, you need to understand every individual part.
To start off, the letters are referring to notes, but more specifically the root notes of keys. The major keys are at the exterior of the circle and their relative minor keys are in the interior. It just means that both keys work well together. You may also see a piece of the staff that includes a treble clef and accidentals. So the letter below each staff is how many sharps or flats the key contains.
There’s a reason it is called the circle of fifths. Each root note is a fifth apart. For example, if you follow the sequence from C to G you get C, D, E, F, G. The key of C has no sharps or flats, which means every note will stay pretty much it is unless there is an accidental in the music. The key of Ab Major or F Minor will contain 4 flats, so you get the idea. Find sheet music for some of your favorite song and try to figure what key they’re in.
Guitar: A Divergent Path 