The Melam-Janaka-Janya system only informs on which type of note is used in the Janya Raagam. The next important information required is the ascending (Aarohanam) and descending (Avarohanam) sequences. As seen earlier these sequences let us know what notes are not used (ex. Mohanam omits ma and ni) and also whether there is devious ('Vakra') ascent or descent (ex. Sahaana 'pa ma ga ma ri ga ri sa' in the descent). The vakra usages are not very strict. For instance Aarohanam of Begada is usually given as 'sa ga ri ga ma pa da pa Saa', but the phrase 'pa da nee da pa' is quite common. For many Janya Raagams different Aarohanam-Avarohanam may be found in different books.
Even in the case of Melakartha Raagams, though the Aarohanam-Avarohanam is given as Sampoorna (complete) (i.e. 'sa ri ga ma pa da ni Sa' and 'Sa ni da pa ma ga ri sa') many phrases involving jumps (ex. 'da Ga Ri ni' in Kalyaani) are used. Some times while describing a Raagam such special phrases are mentioned. The compositions (Krithis and Varnams) are the mainstay to provide guidance in this aspect.
To fully grasp the Bhaavam of a Raaga , one more important feature is needed. That is the manner in which the notes are sung, whether they are held without Gamakam or with Gamakam and if with Gamakam what type of Gamakam, whether a note is touched fleetingly etc. In practice this information is rarely given in books describing Raagams. Some mention important phrases or prominent notes. It is left to the Rasika (connoisseur) or the student to grasp the nuances of a Raagam intuitively by listening to many compositions and Aalaapana. Often experienced listeners are able to grasp the Raaga Bhaavam and identify the Raagam, though they may have no knowledge of the notes.
The importance of Gamakam can be illustrated by playing some phrases of Kalyaani and Sankaraabharanam. The two Raagams differ only in 'ma'. An experienced Rasika can identify the Raagam even when 'ma' is not touched. Listen to phrases (which do not touch 'ma') of Sankaabharanam and Kalyaani covering 'pA dA nI sa ri ga'. The differences are seen in the way in which 'ri', 'ga', 'da' and 'ni' are sung.
Finally being an art form in a system allowing extensive extemporisation, we can never put the description of a Raagam into a straitjacket.
The next 4 pages deal with the 72 melam system in detail and some history behind it. You can jump to Raagam -Essentials, raaga identification etc.