The pentatonic scale is a musical scale having five notes per octave in contrast with the seven notes per octave (heptatonic) of the normal major and minor scales. For example, the five black keys of a keyboard make up a pentatonic scale. Pentatonic scales are thought to have Mongolian and Japanese origins, and form an important part of all far Eastern, African, and Celtic music. Indeed they form the basic of most folk music.
Pentatonic scales may be either hemitonic (containing semitones) or anhemitonic (lacking semitones). Anhemitonic pentatonic scales have become a staple of modern musical forms such as Gospel, blues, and rock because, lacking semitones, they don't have any dissonant intervals. This means any pitches of such a scale can be played in any order or combination without clashing. The two most important are the major pentatonic and the minor pentatonic scales.
Major pentatonic scale
The major pentatonic can be obtained from the diatonic major scale by leaving out the fourth and seventh notes. So, for example, the notes of C major pentatonic are C, D, E, G, A. A. The same end result can be obtained using the circle of fifths. Starting at C and taking five consecutive pitches gives C, G, D, A, and E; then transposing these pitches to fit into one octave gives the C major pentatonic scale: C, D, E, G, A.
Minor pentatonic scale
The minor pentatonic scale can be derived from the diatonic natural minor scale by omitting the second and sixth notes. The three-semitone interval between its first and second notes (a minor third) is what gives it its minor characteristic.
The two pentatonic scales – major and minor – share the same relationship as the diatonic major and minor scales: three semitones down from the major to the minor, and three semitones up from the minor to the major. So the C major pentatonic scale and the A minor pentatonic scale, for example, share the same notes and intervals.
The addition of one note – a flattened fifth – to the minor pentatonic minor scale gives rise to the blues scale.