A Raga (Sanskrit rāga राग,રાગ, রাগ, literally "colour, hue" but also "beauty, melody"; also spelled raag, rag, ragam) is one of the melodic modes used in Indian classical music.
It is a series of five or more musical notes upon which a melody is made. However, it is important to remember that the way the notes are rendered in musical phrases and the mood they convey are even more important in defining a raga than the notes themselves.
In the Indian musical tradition, rāgas are associated with different times of the day, or with seasons. Indian classical music is always set in a rāga. Non-classical music such as popular Indian film songs and ghazals sometimes use rāgas in their compositions.
Joep Bor of the Rotterdam Conservatory of Music defined Raga as "tonal framework for composition and improvisation." Nazir Jairazbhoy, chairman of UCLA's department of ethnomusicology, characterized ragas as separated by scale, line of ascent and descent, transilience, emphasized notes and register, and intonation and ornaments.
The Pentatonic Scale
A pentatonic scale is a musical scale with five notes per octave in contrast to a heptatonic (seven note) scale such as the major scale and minor scale. Pentatonic scales are very common and are found all over the world, including Celtic folk music, Hungarian folk music, West African music, African-American spirituals, Gospel music, American folk music, Jazz, American blues music, rock music, Sami joik singing, children's song, the music of ancient Greece and the Greek traditional music and songs from Epirus, Northwest Greece, music of Southern Albania, folk songs of peoples of the Middle Volga area (such as the Mari, the Chuvash and Tatars), the tuning of the Ethiopian krar and the Indonesian gamelan, Philippine Kulintang, Native American music, melodies of Korea, Malaysia, Japan, China and Vietnam (including the folk music of these countries), the Andean music, the Afro-Caribbean tradition, Polish highlanders from the Tatra Mountains, and Western Impressionistic composers such as French composer Claude Debussy. Examples of its use include Chopin's Etude in G-flat Major, op. 10, no. 5, the "Black Key" etude. Presumably in the major pentatonic.
The ubiquity of pentatonic scales, specifically anhemitonic (without semitones) modes, can be attributed to the total lack of the most dissonant intervals between any pitches; there are neither any semitones (and therefore also no complementary major sevenths) nor any tritones. This means any pitches of such a scale may be played in any order or combination without clashing.