In our Carnatic Music system, we have two different types of Raghas. The first one is Janaka Ragha and the other one is Janya Ragha. Janaka Ragha has many names like Mother Ragha, Melakartha. In all the scale of the raghas, we have two parts. One is the ascending (aarohana) and the other part is decending (avarohana). Mother Ragha is a scale in which all the seven notes are arranged in perfect ascending and the same seven notes are arranged in the perfect decending. That is, SRGMPDNS - SNDPMGRS.

In our music system we have sixteen notes in total. With different combinations of these sixteen notes, the melakarthas are formed. In this system, there are 72 melakarthas. These 72 melakarthas are divided into two groups. The first 36 melakarthas are suddha madhyama melakarthas and the 2nd 36 melakarthas are prithi madhyama melakarthas. In the other way, 1 to 36 melakarthas are with Suddha Madhyamam and 37 to 72 melakarthas are with prithi madhyamam.

The 72 Melakarthas are devided into 12 Chakras. Each chakra has 6 melakarthas. So, in total we get 72 melakarthas. The first 6 chakras are suddha madhyama chakras and the second 6 chakras are prithi madhyama chakras.

Shadjam and Panchamam are constant notes. In Rishabham, Gandharam, Daivatham and Nishadham, there are three different types. In Madhyamam we have two different types.

With all the lowest positioned notes, the first melakartha is formed and with all the highest positioned notes, the 72nd melakartha is formed. This is the introduction of the 72 melakartha system.

Apart from the above Seventy Two Melakarthas, all the other Raghas are Janya Raghas. We have many different classifications in this section. We have to deal them separately.

Theory of carnatic music is very very ancient and this subject has been handled by many many different educationists. The subject is the same because they are fixed and the way of approach only would change. I have also written books in the same subject.