Before we actually get into understanding how a raga comes into being, I think it is essential to delve within the saptak, and explore the aesthetic principles which finally lead to the concept of the raga.
We have seen earlier that it is the relation between two notes (defined by the pitch interval), which decides whether the combination will be pleasing to the ear. Further, the degree of pleasure also would depend upon and vary as per this relation, meaning some combinations will be more favorable than others. The most favorable combinations within the saptak are the pairs of Shadja Pancham and Shadja Madhyam. They are the same actually, the taar Sa becomeing the Pancham of Madhyam.
If you look within the saptak, you would find more pairs which have the Sa-Pa or Sa-Ma relationship. You can extend this to include the komal swaras too. For example, the komal Dhaivat will become the Pancham of komal Rishabh and so on. The clip below would be helpful…..
Based on the Shadja-Pancham Bhaav, we can divide the saptak into two parts, which are symmetrically identical.
The first half, known as the Poorvanga, and the second half, known as the Uttaranga, are perfectly congruent with each other. This congruency, I think, is the fundamental aesthetic principle behind the concept of the Raga. Later, when we look into the Raga formation process, we will realize that the balance between these two parts is an essential factor.
The congruency between these two parts of the saptak also gives us two more availabilities. Firstly, it lets us build phrases in one part which can replicate or compliment themselves in the other. This becomes extremely useful in the development and vistaar of the raga. It is like making a small design in the first half, and then another one matching it in the second half.
Secondly, this congruency also helps the artist hit the right notes. We have seen earlier that we view the swara as a continuum, and the exact points are decided on the specific needs of the moment. Well, this need in turn is more specifically defined by the relationships we want to see and show within the notes. For example, the Dhaivat can be arrived at by imagining it to be the Pancham of the Rishabh, or also as the Madhyam of the Gandhar. And both these points would be different. The exact points or shades of the komal notes employed also would be derived similarly. So, an artist really has to train himself in imagining (visualizing?) the samavaad or the harmonies between the various swara.
Finally, we see that the Poorvanga ends at Pa, while the Uttaranga begins from the Ma, thus including Ma and Pa in both parts. Can you imagine why?
We will find the answer as we move on to see how the Raga evolves from the swara…..