What is Related Raga ?

Refer  What is Janya Raga ?

Some Raaga's notes when shifted using Graha bhedam, yields to other Raagas.

Graha bhedam is the step taken in keeping the relative note frequencies same, while shifting the shadjam to the next note in the rāgam. 

Graha bhedam:

Graha bhedam of a musical scale in Carnatic music (rāgam in South Indian classical music), is the process (or result of the process) of shifting the Tonicnote (śruti) to another note in the rāgam and arriving at a different rāgam.

Graha literally means position and bhedam means change. Since the position of the śruti is changed (pitch of the drone), it is also sometimes called Swara bhedam or Śruti bhedam though Śruti bhedam and Graha bhedam have some technical differences.

Definition:

Modal shift of the Tonic note to higher notes of a rāgam, while retaining the note's positions (swara sthānas – sthāna means position/ pitch), results in different rāgams. This is called Graha bhedam.

Practical demo

A simple practical demonstration of Graha bhedam can be taken up by playing the structure of a rāgam with the drone set to Sa (Shadjam). Then if we keep playing the same keys/ notes, while shifting the drone to another note in the rāgam, to form the new śruti/ tonic note, the result is a different rāgam.

Example Illustration:

When Graha bhedam is applied on Shankarabharanam's notes, it yields 5 other major Melakarta rāgams, namely, Kalyani, Hanumatodi, Natabhairavi, Kharaharapriya and Harikambhoji.

Rāgam	Mela #	Śruti Tonic	C		D		E	F		G		A		B	C		D		E	F		G		A		B	C
Shankarabharanam	29	C	S		R2		G3	M1		P		D2		N3	S'		R2'		G3'	M1'		P'		D2'		N3'	S' '
Karaharapriya	22	D			S		R2	G2		M1		P		D2	N2		S'
Hanumatodi	08	E					S	R1		G2		M1		P	D1		N2		S'
Kalyani	65	F						S		R2		G3		M2	P		D2		N3	S'
Harikambhoji	28	G								S		R2		G3	M1		P		D2	N2		S'
Natabhairavi	21	A										S		R2	G2		M1		P	D1		N2		S'
Invalid Melakarta	–	B												S	R1		G2		M1	M2		D1		N2		S'
Shankarabharanam	29	C	S		R2		G3	M1		P		D2		N3	S'		R2'		G3'	M1'		P'		D2'		N3'	S' '

Notes on above table

• C as the base for Shankarabharanam is chosen for above illustration only for convenience, as Carnatic music does not enforce strict frequency/pitch structure. The Shadjam (S) is fixed by the artist as per the vocal range or the instrument's tonic note. All the other swarams are relative to this Shadjam, falling into a Geometric progression-like frequency pattern. This note is applicable to all tables that are illustrated further below in this page.
• The 6th Graha bhedam of Shankarabharanam has both Madhyamams (Ma) and no Panchamam (Pa) and hence will not be considered a valid Melakarta (ragam having all 7 swarams and only 1 of each). This is only a classification issue with respect to Melakarta, while this structure could be theoretically used well to create good music (probably needs an expert).
• The gaps in the above table are for the missing swara positions in these ragams, which happens to be the Sharp / Flat notes in western music.

Melakarta rāgams:

Graha bhedam can be applied on most Melakarta rāgams to yield other Melakarta rāgams (16 of the 72 do not yield any valid Melakarta scale). When applying such modal shift of tonic note, some results are not valid Melakarta rāgams (rules of the definition of Melakarta are violated). Example scenarios are missing Panchamam (Pa) or two of particular note (Rishabham (Ri), Gandharam (Ga),Madhyamam (Ma), Dhaivatham (Da) or Nishadham (Ni)).