Circle of Fifths

a graphic diagram of keys showing how they are related. The keys of C major and A minor are placed at the top of the circle; moving clockwise from them the major and minor sharp keys are arranged in perfect fifths, and the flat keys are arranged moving counterclockwise. To construct the sharp and flat keys of all 12 tones of the octave, the movement in both directions must be full circle. Here each key will have an enharmonic equivalent. Since keys having more than seven sharps or flats are not used in reality, the sharp and flat keys close up into a common circle of fifths, joining with their enharmonic equivalents in its three lower links.