Circle of thirds
Common method of organizing pitches and keys. / From Wikipedia, the free encyclopedia
In music theory, the circle of thirds, also known as the cycle of thirds, is a way of organizing pitches, and is a foundational pattern in music. This cycle is expressed through a sequence of 24 keys and therefore notes, which are changed by shifting up or down by a major or minor third. This in turn will lead to a noticeable visual pattern (a circle) and an auditory pattern (interconnected pitches), which are derived from the chromatic scale. Starting from C, the cycle goes as follows: C, Em, G, Bm, D, F♯m, A, C♯m, E, G♯, B, D♯m, F♯/G♭, B♭m, D♭, Fm, A♭, Cm, E♭, Gm, B♭, Dm, F, Am, and back to C.[1][lower-alpha 1]
The circle of thirds is formed by placing the notes of a major or minor scale in order of thirds, instead of in their ascending order of scale degrees. In other words, this pattern is not dependent on a position within a scale, rather a sequence of thirds. When in a key other than C, the sequence will not start from C, but it will still be in the same overall order when viewed as a circle.[2]