The pentatonic scale is one of the most widely used and basic patterns in music history, and it is found in cultures around the world and dating as far back as 2000 B.C. It was made popular in Western classical music in the late nineteenth century when French composer Claude Debussy diverged from the structure of diatonic music and began to experiment with theories he learned from East Asian music, particularly Chinese, Japanese and the Javanese gamelan.
The pentatonic scale is based on the number 5 because it has 5 pitches in it, but also because it is formed by the circle of fifths. The pitches of the major pentatonic scale can be found by counting up the circle of fifths: for example, if the root note is C, the scale will have G, D, A and E (or, in order, C-D-E-G-A). A quicker way to find the scale is to omit the 4th and 7th scale degrees from a major diatonic scale. Even more quickly, find a pentatonic scale by playing the black keys on a piano.
The minor scale is another type of pentatonic scale, found by playing the same pitches as its major relative, but starting a third below (for example, playing the C major pentatonic scale starting on A creates the A minor pentatonic scale). Less common classifications are hemitonic, when the scale contains semitones, and anhemitonic, when no intervals are smaller than a whole step.
The pentatonic scale is often found in folk music, such as the melodies of "Oh, Susanna!" And "Auld Lang Syne." You can also hear it in much of Debussy's work, such as in "Clair de Lune." It is also common in rock. Mostly, though, in popular Western music, the minor pentatonic scale is known as the basis for improvisation in blues.
Many listeners hear a distinctly Asian flavor in the pentatonic scale. A solo in minor pentatonic, though, sounds bluesy. It sounds dreamy and impressionistic when played in the higher register of a piano. Overall, it is popular and universal in part because it is simple and can be used in almost any genre and because of its inherent consonance, meaning it almost always sounds, simply, pretty.