The Circle of Fifths

Arrange the twelve keys so each is a fifth above the last and they close into a circle: C, G, D, A, E, B, and onwards through the flat keys back to C.

The arrangement is useful because neighbouring keys are nearly the same. C major has no sharps. G, one step clockwise, has exactly one. D has two. Each step adds a single sharp and changes a single note, so keys next to each other on the circle share almost all their notes — which is why songs move between neighbouring keys smoothly and why a key two steps away sounds like a bigger event.

It also gives you the relative minors from lesson seven at a glance, and it explains why V to I is such a strong movement: V is always the key's clockwise neighbour.

Circle of Fifths

Start at C and go clockwise, naming the sharp each key adds. Then find each major key's relative minor.

Now the practical payoff. Guitars are comfortable in a few keys and awkward in the rest, because open chords only exist in some of them. A capo fixes this by shortening every string at once, which raises everything by however many frets it sits above the nut, letting you play easy shapes in hard keys.

This track is in D minor, moving between D minor, B flat, F and C. Two of those — B flat and F — are barre chords, which is a lot of work for a beginner.

Put a capo on the fifth fret and play A minor, F, C and G shapes instead. Five frets up, A minor sounds as D minor, F sounds as B flat, C sounds as F and G sounds as C. Three of the four become easy open shapes, and only the F shape stays a barre. The sound is identical; the effort is not.

B♭

B flat major — the barre chord the capo lets you skip.

Capo Transposer

Put the capo at the fifth fret and check the maths: A minor becomes D minor, C becomes F, G becomes C.

D minor, B flat, F and C. Try it without a capo, then with one at the fifth fret.