Chhandah Shastra, dealing with the Rig-Veda and Yajur-Veda is a treatise on chhandas or metre, and gave its name to one of the six Vedangas, inaugurating a considerable literature on the subject and thus becoming the starting point of prosody. In Pingala's work, which belongs to the sutra type, we find for the first time the use of algebraic symbols. A later work on Prakrit measures is also attributed to Pingala. Works on metre were written by or ascribed to Kalidasa, Vararuchi and others.
Classical Sanskrit metre is quantitative, as in Greek and Latin, based on long and short syllables, and not, as in English, on stress. The unit of quantity is the matra, which is the time taken to pronounce a short vowel. A long vowel counts as two matras, and a vowel is long according to its nature or position. The final effect of a Sanskrit verse depends on the vritta, 'turn' a combination of factors including metre, accent (where it exists), number of syllables, and the rhythm of the verse ending.
The 'ideal' verse or stanza consists of four lines, like the four 'feet of a quadruped. Each line is called a pada (lit. `foot'), which term is not used in the same sense that foot is used in English Prosody i.e. consisting of two or three syllables. The Sanskrit pada represents the metrical unit, and the term pada can mean, 'foot', 'quarter', 'fourth', or simply, 'line'. Each pada or line generally consists of from eight to twelve (sometimes even more) syllables, although a shorter or syllabic line is also employed. There are five principal metres, namely:
1)Gayatri (from the Gayatri mantra), a Rig-vedic metre consisting of three sections of eight syllables each.
2)Anushtubh, a stanza of four lines of eight syllables each.
3)Shloka, a loose measure developed from the Vedic anushtubh, it also consists of four padas of eight syllables each.
4)Trishlubh, consisting of four padas of eleven syllables each with a caesura after the fourth or fifth syllable.
5)Jagati, like the trishtubh, consisting of four padas, but with twelve syllables per pada.
The commonest of the lesser metres are: viraj, consisting of padas of thirteen (sometimes ten) syllables; it is to be used by those who desire abundant food; sakvari, consisting of fourteen syllables to the pada; atisakvari, nineteen syllables to the pada; it is used by those who desire life; brihati, thirty-six syllables to the pada; to be used by those who desire prosperity and glory.
In addition to these there are some metres determined not by syllables but entirely by the short vowels (matra) they contain, the most famous being the arya metre, also called the gatha.