The circle of fifths

The circle of fifths puts all twelve keys in a ring, arranged so that neighbours are closely related. It looks like theory, but it is a practical tool: it tells you how many sharps or flats a key has, which keys sound good next to each other, and which chords are likely to follow each other.

Start at C at the top. Each step clockwise moves up a fifth, five letter names along the alphabet, and adds one sharp:

Going anticlockwise from C moves down a fifth each time, and adds one flat: F has one flat, Bb two, Eb three, and so on round the left-hand side.

Two things to read straight off the circle:

• The keys either side of any key are its closest friends. Around G you find C and D, which are exactly the IV and V chords of G. Take any key, and the chords to its left and right are its most important chords.
• The inner ring shows each key's relative minor. Under C is Am, under G is Em. The same notes, a different home.

Put the two together and you have most of a key's chords from one glance at the circle. For G: G itself, C and D either side of it, and the minors inside those three, Em, Am and Bm. That is all six of the chords of G major you use regularly.

That is the end of the course, for now. You can hold the guitar, tune it, play the open chords, their minors and power chords, find notes on the neck, play both pentatonic boxes, and understand keys. That is a real foundation. Go and use it on the songs you love: upload one to OnPitch, look at its key and chords, and play along.