Sudha Madhyama and Prathi Madhyama Ragas

Sudha Madhyama and Prathi Madhyama Raga:

There are seventy two melakartha ragas each with its own set ot janya ragas.
As mentioned before ragas can take variations only in Re (R1,R2), Ga (G1, G2), Ma (M1, M2), Da (Da1, Da2) and N (N1, N2).

The first 36 of 72 melams use Sudha Madhyamam (M1) and are called Sudha Madhyama ragas. The later 36 use Prathi Madhyaman (M2) and are called Parathi Madhyama ragas. So within each category they can differ only in Ri, Ga, Da and Ni. These are systematically divided into six chakras, with six melams per chakra.