The two terms Arohana (ārōhaṇa) and Avarohana (avarōhaṇa) are used in Carnatic Music as a terse formula/description of the order of swaras (notes) in a carnatic raga i.e. a decription of the raga’s structure. The Hindustani system calls the same terms Arohi (ārōhi) and Avarohi (avarōhi) respectively. The arohana defines the ascending order of swaras in the raga, and avarohana defines the descending order. The arohana and avarohana are orthogonal in that the ascending order and descending order can be different for a raga. In Western Music, this is rare (e.g. some versions of the melodic minor scale). In Indian classical music this is very common. I believe it is rare in Western Music perhaps owing the dominance of harmony, whereas it is common in Indian classical music owing to the dominance of melody.

The asymmetry in arohana and avarohana comes in many forms

  • Different number of swaras between arohana and avarohana (e.g. sAvEri, vasanta, maNirangu etc.) – this is very common
  • Same number of swaras in arohana and avarohana but different flavors (e.g. brindAvana sAranga and some interpretations of bhairavi)

Linear vs. Non-Linear arohana/avarohana: On top of this, the arohana and/or the avohana can be linear or non-linear.

  • A linear arohana has the set of swaras laid out in increasing order of pitch (e.g. S R1 M1 P D1 S for sAvEri). Similarly a linear avarohana has the set of swaras laid out in decreasing order of pitch (e.g. S N3 D1 P M1 G3 R1 S for sAvEri).
  • A non-linear arohana/avarohana may have zig-zag (vakra) patterns, and/or special phrases included in it.  For example,  SrIraga is a case that has both. Its arohana is a simple linear S R2 M1 P N2 S. The avarohana however is S N2 P D2 N2 P M1 R2 G2 R2 S. Here P D2 N2 P M1 is a special (but rare and non-mandatory) phrase, and the only one that can include dha. The M1 R2 G2 R1 is the vakra/zig-zag where while descending from ma, you cannot go to ga directly but must go to ri, then ascend to ga, and then back to ri. This is mandatory in SrIraga.

This indicates that the arohana and avarohana come in various flavors with potentially a lot of complexities implied. In fact, in complex phrase oriented ragas (e.g. nATakurinji, Anandabhairavi, rItigowLa etc.), the arohana and avarohana fall short of being fully representative of the raga structure, and thus become less useful, and also potentially misleading. There is also subjectivity and inconsistency which comes into play in these cases (e.g. are all special phrases included?).

In the simplest case of linear and symmetrical arohana/avarohana (e.g. all melakarata ragas, and ragas like mohanam etc.), as well as the simplest form of asymmetrical arohana/avarohana where both of them are linear, the terms do serve quite well.

Confusion regarding interpreting simple asymmetrical arohana/avarohana:
One of the interesting confusions some rasikas of carnatic music have is regarding the interpretation of the asymmetrical arohana and avarohana – even for the simplest case where both are linear.  Let us take one such raga – sAvEri. Its arohana and avarohana is as follows:

arohana: s r1 m1 p d1 s

avarohana: s n3 d1 p m1 g3 r1 s

As you can see there is no ga and ni in arohana but both are in avarohana.  Now what does this mean?

  1. Is s r g r allowed?
  2. Is the phrase d n d m allowed?
  3. How about the phrase n d n s?

Many rasikas look at the arohana s r m p d s and conclude that all three must be disallowed.  But in truth,  only #3 is disallowed.  When rasikas encounter #1 and #2  in concerts (e.g. kalpanaswaras), they may conclude that “Well – sAvEri must really be a special raga whose usage defies easy representation”.  Now there are indeed ragas whose arohanas/avarohanas are not fully representative, but in this case, there is actually a logical explanation that follows directly from the arohana and avarohana as to why #1 and #2 are allowed, and why #3 is not.

To get there, let me state the rules of interpreting linear (i.e. on-vakra, non-phrase-oriented) arohanas/avarohanas:

  1. You can ascend from a swara, if it appears in the arohana. In other words, if a swara appears in the arohana, you can ascend from it.
  2. You can descend from a swara if it apppears in the avarohana. In other words, if a swara appears in the avarohana, you can descend from it.

Simple isnt it? But what is the big deal? It perhaps seems obvious!

I think one of the main reason why folks (I was one some time ago) may conclude that the first phrase (s r g r) as disallowed is that they see the s r m as arohana of sAvEri, match it against s r g r – and immediately conclude that s r  g combination is disallowed. For some odd reason, many of us initially seem to easily fall for this. However, this considers the half of the picture as in just arohana. The arohana does indeed says s r m – but the avarohana has m g r s and that is being left out in reaching such a conclusion! In fact, if we apply the rule above, we will find that s r g is certainly allowed as long as we descend from g after 🙂

Now let us look at these phrases and methodically apply our rule:

  • #1: s r g r:
    • Take the first transition i.e. s r. We are ascending from sa. This is allowed because sa is in arohana.
    • Take the next transition i.e. r g. We are ascending ga here. This is also allowed because ri is in arohana.
    • Take the next transition i.e. g r. We are descending from ga here. This is allowed because ga is in avarohana.
    • Since all transitions are allowed, the phrase is allowed. If you are still not convinced, you may want to note that this is pretty much how the sAvEri varnam starts (as s r g r g ri <=> sa ra su . . Da)
  • #2: d n d m:
    • First transition d n is allowed as we are ascending from dha, and dha is in arohana
    • Next is n d, which is allowed as we are descending from ni, and ni is avarohana
    • Next is d m, which is also allowed as we are descending from dha, and dha is also in avarohana
    • Since all transitions are allowed, the phrase is allowed. This phrase also occurs (more than once) in the sAvEri varnam.
  • #3: n d n s:
    • First is n d, which is allowed as we are descending from ni and ni is avarohana
    • Next is d n, which is allowed as we are ascending from dha and dha is arohana
    • n s is disallowed as we are ascending from ni, and ni is not in the arohana
    • Since the last transition is disallowed, this phrase is disallowed – not because of n d n, but only because of n s.  The n d n as such is allowed but only as long as we descend from ni after that which we did not do here.

As an exercise for the reader, see if following are allowed or not:

  1. For sAveri,
    • s g r  for sAveri  (can you find a rendition which includes this phrase?)
    • d G R S (capital implies tara stayi or higher octave)
  2. kAmbhOji , whose arohana is S R2 G3 M1 P D2 S, and avarohana is S N2 D2 P M1 G3 R2 S (ignoring S N3 P which a rare, special phrase):
    • d n d m p d n da
  3. nATa/nATTai whose arohana is S R3 G3 M1 P D3 N3 S. And avarohana is S N3 P M1 R3 S.
    • p m g r s
    • p m g m p
    • p m r g m p
    • p d p

Limitations of applicability of above rule:
The above rules should work for all ragas whose arohana and avarohana is linear (symmetrical or not). The non-linear world is sort of fraught with inconsistencies – but I believe for some cases (e.g. mandatory vakra as the only additional feature) logical rules can apply. I will try to post on that later.