Indian music is based on melody and the raga is pivotal to the system. Raga (what which pleases) is a melodic structure governed by rigid rules but it allows the practitioners a great deal of freedom to improvise. Ragas are derived from scales with particular combinations of notes with a definite relationship to the tonic which when sung evoke certain moods and emotions. The swaras of a raga have to be strictly adhered to and only permitted deviations which enhance the aesthetic quality of the raga are possible.
A peculiar and inseparable part of Karnatak ragas is the gamaka. To explain this complex term it would be ell to quote Professor Sambamoorthy, the greatest authority on Karnatak music of the 20th century: "Gamaka is a collective term given to the various shakes, graces, ornaments and embellishments used in Indian music. It constitutes another dimension in music. In other words when the plain character of a note is altered so to result in a musical effect it becomes a gamaka".
The slower the tempo of singing the greater is the scope for the manipulation of a swara. The fast tempo tends to slur over gamakas and rob the raga of its essential character. Some ragas like Todi, Varali, Bhairavi, Begada, etc., are heavily gamaka-oriented and singing them without the right oscillation of the notes would destroy their identity. Todi, for example, sung without gamaka would turn into Sindubhairavi which corresponds to Hindustani Bhairavi. Ragas like Hamsadwani and Bilahari and some minor ragas do not have gamakas.
Desribing Karnatak music as "near-perfect" a contemporary musician, T.V.Goalakrishnan, who has been trained in Karnatak, Hindustani and Western systems says: "Notes are plain in Hindustani and Western music, while in Carnatic, they are given 'gamaka' (resonance) and thus made more lively" (The Hindu, 2 May 1997). He adds that it is this reliance on microtones that lends a distinct character to Karnatak music.
Gamakas make notation of music difficult as they can only be taught by the oral method. Notation in Karnatak music is only as useful as the script of a play to an actor. It makes a musician aware of the structure of a Varnam or kriti but the actual rendering of it has to be learned from a guru.
The Madras Quartet by Indira Menon, Roli Books, New Delhi, 1999