Alamkara shastra is the knowledge of poetical or literary 'adornment', sahitya or rhetorical composition and the art of verse (the Sahitya-darpana or mirror of poetry is the title of a fifteenth century work on Poetics); rasa-shastra, good 'taste' and discernment in art and letters. Much of the Poetics is devoted to this subject of rasa and the rasika. A man of taste and culture is invariably acquainted with the art of poetical writing.
Essentially, poetry is ruled by convention or agreement (samgati), but within the framework of the rules. The imagination (pratibha) of the poet must have freedom to produce that peculiar charm (vichchhitti) which distinguishes true poetry from ordinary work on subjects like logic or philosophy. One of the basic notions of poetics is that of dhvani, 'suggestion' or overtone, which consists in not stating everything but leaving much to be understood. Dhvani makes use of allusion, oblique reference, suggestive and evocative terms of speech, which create in one the mood desired. Dhvani is regarded by some writers as the chief element of poetry.
Other important features of a good poem are: perspicuity (prasada), although this must not be overdone; sweetness (madhurya), also in moderation; where necessary there should be gentleness (sukumarata) to give the poem grace (kanti); it must possess a sequence of thought (arthakrama), breadth of meaning (audarya), and completeness of sense (paripurnata). Sophistication and learning are added to give it elegance (upanagarika) and charm (sobha) and the proper dignity or elevation (udaratva), thus combining to produce aesthetic pleasure.
The methods by which such aesthetic pleasure is achieved constitute the province of alamkara, 'adornment'. The word is said to be composed of alam-kara, 'enough-making', i.e. that which helps to make adequate something that lacks adornment. The term covers the whole technical apparatus of poetry, the devices of prosody, and rhetorical embellishments, particularly vyanjana.
The term vyanjana, 'ornament' or figure of speech, covers all terminological and syntactical devices, employed to enhance the effect of expression. The chief vyanjana are as follows; upachara, 'compliment', often used as a synonym for figure of speech, rapaka, 'image' or metaphor, makes use of the image of one thing to increase the effect of another; upama, 'simile' or comparison, aropa or figurative substitution; the metonymy or synecdoche; utpreksha, figurative 'vision' frequently used with the historic present; sara, 'augmentation' a form of climax, or a stepping up from the simple to the complex; vyaja-stuti, 'feigned praise' of something; anukarana, 'imitation' or onomatopoeia, where the sound echoes the sense; in Sanskrit the aspirated consonants lend themselves to this form; ajanala, 'implied' or understood but not expressed, an ellipse; anuprasa, `alliteration', where the same sound is frequently repeated; vakroti an oblique or indirect mode of expression; the suggestive double entendre; yamaka, the pun; the use of words identical in sound but different in meaning; atisayokti, 'hyperbole' or poetical exaggeration; slesha, 'union', an effective and euphonious combination of sounds etc. Dandin, author of a work entitled with styles of composition, ornamentation, metrical tricks and puzzles is a precursor of the riti (style) school, and he has made an important contribution to the poetic concept of guna or quality, as distinct from mere expression of language as the primary concern of poetry. Vamana, in the latter half of the eighth century held that riti was the soul of poetry. Ananda-vardhana, is the principal exponent of the dhvani school. His dhvanyaloka was commented on by abhinava-gupta. Mammata whose `kavya-prakasha gave a comprehensive survey of all his predecessors and became the source of several later theories.