Raga or Ragas(in plural) is basic musical modes which express different moods in certain characteristic progressions, with more emphasis placed on some notes than others. In the traditional Indian classical music, ragas are associated with different times of the day, or with seasons. Indian classical music is always set in a raga. The various time zones for ragas are - Morning, Afternoon, Evening, Night and Anytime. When performed at the suggested time, the raga has its maximum effect. There are few ragas which are performed based on the season. e.g. Gaud Malhar and Miyan Malhar rag sung in monsoon.

Ragas are derived from scales, so let's try to understand what a scale is.

An octave has 12 notes. A scale is a musical theme created by choosing a specific set of notes from within these 12 notes. 

The idea of scales is actually quite fundamental to all music. The music of ancient Greece was based on modes, which are similar to scales. In Western music today, you have major, minor, pentatonic, jazz, blues, and other scales. 

A scale is just a prescribed set of notes. So long as you use only those notes, you can combine them in any way you want. A raga is a bit more specific. Within the framework of the scale, the ascending and descending scales (aaroh and avroh) are defined separately. This makes it possible to get many ragas from each scale. 

Aroh & avroh

The first things you learn about a raga are its ascending (aaroh) and descending (avroh) scales. The aaroh and avroh greatly influence how musical phrases in a raga are structured. If a note is skipped in the ascending scale of a raga, musical phrases in that raga will reflect this by always skipping that note in ascending sequences.

Classification Systems of Raga

There are hundreds of ragas, and they can be classified in various ways – by structure, by parent scale, by family, by time or season, by mood, and so on. The seasons and moods ascribed to ragas are more subjective, but classifying by structure, scale, or family helps to get a better understanding of ragas from different perspectives.


Raga Classification by Structure (jaati)

Ragas are classified by structure based on the number of notes in their ascending and descending scales. Also, many ragas use different variants of the same note on the way up and down. Taking both the above into consideration, I like to think of ragas as being symmetric or asymmetric. Additionally, in terms of raga structure, we also have circuitous ragas, mixed ragas, and compound ragas.


Raga Classification by Scale (thaat)

Another way of classifying ragas is under the ten parent scales (called thaat). For instance, ragas that use flat ga and ni (♭3 & ♭7) and are classified under the Kafi scale, ragas that use flat re and dha (♭2 & ♭6) are classified under the Bhairav scale, and so on.


Raga Classification by Family (raagang)

A lot of ragas have been created from other ragas, giving rise to entire families (called "raagang"). The family-based classification system groups ragas based on their shared origins and melody profiles.