Both Sahana and Dwijavanthi have a structure that makes them melodic and appealing.
Here is another pretty pair, in the sense of beatific melody that is innate in the very structure of these ragas. Whatever be the language of the composition it is bound to be appealing to the ear -this duo is Sahana and Dwijavanthi, both off-shoots of the 28th melakarta, Harikambhoji. While Sahana evokes Karuna and Shanta rasas (emotive experience), Dwijavanthi is laden with devotion, also Karuna.
To a certain extent both the ragas do not find a mention in ancient musicological texts. Sahana was popularised in the period preceding the Trinity. Dwijavanthi is not a purely Carnatic raga; it has been imported from Hindustani strain where it is known by the name of Jayjayawanthi. This raga was referred to in the Sangeetha Makaranda as Dwijayavanthi (Dwija means the twice-born). This nomenclature got distorted in both North and South musical parlance in time to come and hence we now talk of Dwijavanthi or Jayjayawanthi. It is not merely the musical format that defines allied ragas; it is the way in which the swara (notes) phraseology (prayogas) is used that marks the finer nuances of the ragas and distinguishes them from each other.
For instance, the ascent (aarohana) structure of Sahana goes as: ‘Sa-Ri2-Ga3-Ma1-Pa-Ma1-Dha2-Ni2-SA’ and its descent (avarohana) is ‘SA-Ni2-Dha2-Pa-Ma1-Ga3-Ma1-Ri2-Ga3-Ri2-Sa’ which takes Chathusruthi rishabha, Antara gandhara, Shuddha madhyama, Chathusruthi daivatha and Kaishiki nishadha. The Dwijavanthi’s ascent-descent is ‘Sa- Ri2-Ga3-Ma1-Pa Dha2- SA’ and ‘SA-Ni2-Dha2-Pa-Ma1-Ga3-Ma1-Ri2-Ga2-Ri2-Sa’ respectively. Musicologists state that ‘when a raga is adapted to a system, it invariably takes the aid of an established raga.’ Dwijavanthi when adapted to Carnatic music takes the help of ragas like Sahana.
Sahana is termed an ubhaya vakra sampoorna raga. Ubhaya means both and vakra means not straight. It means the notes of this raga do not follow a steady progression but go on a zig-zag pattern. Hence the raga is bestowed with a unique feature that lends to its beauty. Yet Sahana contains all the seven notes like a sampoorna raga. Sahana’s characteristic phrases are ‘ri, ga, ma, pa’ and ‘pa, ma, dha, ni,’ ‘ni,sa, dha’ and ‘ga, ma, ri.’ These phrases create a distinct mood in the raga with their characteristic gamakam. Varied gamakam is the backbone of Sahana like the oscillating gamaka (kampitam), pratyahatam (ni-dha, dha-pa, pa-ma). The distinct but variant gandhara swara is the characteristic aspect of this raga. The effective combination of gamakas with swaras generates that aesthetic experience called rasanubhava in this raga.
However if we take a look at the technical differences between Sahana and Dwijavanthi, we would derive a greater experience. Sahana uses the ‘antara gandhara’ whereas Dwijavanthi uses both the ‘antara’ and ‘sadharana gandhara’, adhering of course, to certain rules of the game. For instance, if we were to use something like ‘pa-ma-ga-ma-ri-ga-ri-sa...’ then, the first ‘ga’ ought to be ‘antara gandhara’ while the second one would be ‘sadharana gandhara’.
The same is not true of Sahana which uses only ‘antara gandhara’ at both places. It is the ‘rishabam’ (ri) which is the mischief-maker as in both the ragas it sounds the same (there is a special usage where it sound like ‘ri+ga’). Dwijavanthi lays stress on the ‘daivatha’ and ‘rishaba’ in prayogas (phrases) like ‘pa-dha-ni-dha...’ ‘pa-ma-ga-ma-ri...’or ‘dha-dha-ma-dha-ni-dha-pa-ma-ga-ma-ri…’
Sahana’s popularity in ragamalika and slokas is more due to the raga’s felicity in swara rendition. Hence there are as many as 85 compositions in Sahana. Of the ten compositions of Thyagaraja, ‘Giripai Nelakonna’, ‘Ee Vasudha’, ‘Raghupate Rama’, ‘Vandanamu Raghunanadana’ are very popular. Muthuswami Dikshitar's ‘Sri Kamalambikayam’, ‘Abhayambayam’ and ‘Easanadi Sivakara’ are wrought with classicism in this raga. The famous ‘Akhilandeshwari rakshamam’ of Dikshitar is quintessential Dwijavanthi for you.