The Natyasastra probably had 6000 verses distributed in 36 chapters. It has a well-known commentary Abhinavabharati of Abhinavagupta which, however, is available only in fragments. Other writers known to have commented upon the Natyasastra are: Bhattanayaka, Harsa, Kirtidhara, Lollata, Matrguptacarya, Sankuka and Udbhata. None of these, however, is available now.
The main subject of the Natyasastra is dramaturgy. Bharata's Natyasastra names ten forms of drama (Dasarupaka). He also develops the theory of rasa in poetics. Figures of speech like upama (comparison or simile), rupaka (metaphor), dipaka (enlightener) and yamaka (same word with double meaning) are enumerated by him. He also narrates ten gunas (excellences), ten dosas (defects and thirty six laksanas (characteristics) of a poetical composition.
The Natyasastra's scope is so vast that it includes legendary accounts about the descent of drama from heaven to earth, the construction of diverse theatres, the worship of stage divinities by performers. varieties of dance like tandava, forms of histrionics with minute details regarding gestures of hand, eye, etc., the languages to be employed by different characters, the prosodial measures admissible, the elements of music, vocal as well as instrumental, the costumes required, the use of curtains diverse forms of plays, the elements of plot with junctures and sub-divisions, types of characters, varieties of heroes and heroines rasas or sentiments, bhavas or emotions, alankaras or figures of speech, gunas or literary qualities and dams Or defects, besides numerous items of incidental interest. While the earlier items are of technical interest to actors and performers or students of the arts of dance, music and even painting, the other concepts beginning with raw become relevant to literary criticism as well as aesthetics.
According to the Natyasastra, the general aim of all drama is to provide entertainment to people at large weighed down by their trials and tribulations in life (I. 14).
Whatever the dramatic type, the plot should involve a conflict which is resolved at the end. It will be clearly divisible into units like the opening, where the forces for and against are almost equally ranged, the complication where the end intended becomes almost unrealizable, and the denouement which shows the ultimate victory of the hero’s endeavours.
In the end the Natyasastra rules that virtue must triumph over vice. This shuts out almost the prospect of any real tragedy in Indian drama. The Natyashastra states openly that morality, wordly prosperity and fulfilment of the heart’s desires should motivate the best characters and their lives should serve as models for the onlookers to fashion their own lives.
The Natyasastra is perhaps the most complete theoretical statement in the world heritage on the entire poetic circuit: the latent affective reactivity of man, its activation by the organization of various kinds of stimuli in the dramatic presentation, the reaction to it by the spectator, and its final distillation into a pure aesthetic relish.
By all counts, the most outstanding contribution of the Natyasastra to aesthetics and art activity is his theory of rasa, usually translated as sentiment for want of a better word. In Sanskrit its connotation has a wide spectrum including ‘taste’, ‘delight’ and ‘sap’. Rasa is said to be the quintessence and life-breath of every element in a play—whether representation, plot, style, costume, music or dance. Writers on painting extended its scope to that art also. But the concept of rasa is so inextricably bound up with that of bhava or emotion that one cannot be understood without the other. In usage rasa-bhava is almost an interchangeable single concept.
In the Natyasastra's perceptive and illuminating analysis the raw- material of art or life which it tries to improve upon is none other than the mental world of man bristling with feelings, emotions and sentiments driving him to activity all the time. But the actual passions in the world are not artistic in themselves. Mental states in life axe accompanied with their pleasures and pains. However, when an artist turns to them, he puts them into a pattern of his own making in his imagination, a pattern which never existed on earth. Only these patterned mental states, obeying a law of creative genius or imagination, deserve to be technically called bhavas. The process of creative imagination itself is bhavana which is tantamount to aesthetic sensibility. This is the first pre-requisite as much of the playwright as of the spectator (bhavaka or rasika).
The Natyasastra observes:
There is no rasa without bhava: Nor any bhava without raw, in staging, success depends on their mutual involvement. (VI. 36). When a subject or bhava finds a ready echo in the spectator it is transformed into rasa then and there. His whole hod3 will be on tire with it as dry fuel caught by fire (VII. 7).
The principle of a ruling dominant sentiment amidst a variety of rasas as the key principle for, the success of any drama is the Natyasastra's greatest contribution to dramatic criticism. He states:
When, in the midst of diversity of psychic states, all transfigured by the imagination, there is one master-passion unifying all of them like a thread; that is to be regarded as the ruling sentiment of a work of art, the rest are but momentary. There is noting like a single rasa in drama (VII. concluding verses).