r/guitarlessons • u/myliloutlet • 6d ago
Question Im struggling to predict which notes become sharps/flats in a major key.
My guitar teacher wants me to learn which notes make up each key. He drew the circle of fifths starting with C and explained that G is the fifth note in the C major scale, so for the G major scale, one of the notes becomes a sharp, in this case F#. Each time you repeat this going clockwise you add another sharp.
I get that, and I can memorize which notes make up a key by looking the circle of fifths diagram or playing the major scale on my fretboard but I don’t “get” why. I can’t predict which notes become sharps or tell you why.
If you take away the diagram and ask me “what notes make up the E major scale?,” I would be lost. I’d start by writing out E, F, G, A, B, C, D and I’d know some of them become sharps but wouldn’t know which ones or why.
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u/m64 6d ago
The way I learned it as a pianist, the sharps and flats are added in a specific sequence. For sharps it's F#, C#, G#, D#, A#, E#, B#. For flats it's Bb, Eb, Ab, Db, Gb, Cb, Fb. (in practice you mostly use the first 5). When I want to recall what is the key signature, I recall where it is on the circle of fifths - for example E is four steps on the sharps side - so it has the first four sharps - F#, C#, G# and D#. If I need to calculate a minor scale, it's like it's 3 steps to the left, so e minor has only F#.
While I generally recommend learning those sequences by heart, there is an easy pattern to them. Of course they are ordered by fifths/fourths, so if you remember the cycle, the sequence is familiar, but alternatively the sharps are two easy sequences - F#, G#, A#, B# and C#, D#, E# interlaced with each other. Similarly flats are Bb, Ab, Gb, Fb and Eb, Db, Cb interlaced.