Excepting the mela 56 of the first kirtana ie camaram the scales of all ragas used in this series are connected by grahabedha which means that each scale can be derived from the other without changing any note but by changing the starting note.

 

Since the seventeenth century north Indian musicologists such as Ahobala,Naryanadeva, locana and bhatkande tried to classify raga according to a limited number of basic scales(ten twelve) six of which are always identical with the above mentioned six related murchana.

tyAgarAja vibhakti kritis 

In  a series of 8 vibhakti to the god tyagaraja of Tirivarur the first seven songs are musically connected by grahabedha principle since their raga belong to the mela 22 ,28,29 or 65 while only the eighth stands by itself.Dikshitar may have arranged these in a series of 7 + 1 in conformity with the temple legend which says that once king Muchukunda received the somaskandamurti idols ( 1 original + 6 copies) from Indra after he had discovered the original one among the 7 images with the help if Shiva.The eighth song in viravasantham can be considered as a mangalam or concluding piece as its pallavi ends with jaya often found in mangala compositions.