The essentials
Chandas (metre) is the study of the rhythmic structure of verse. The classic text is Pingala's Chandahsutra. Indian prosody classifies syllables as laghu (light) or guru (heavy). A syllable is guru if it has a long vowel, or a short vowel followed by two or more consonants (or by anusvara/visarga); otherwise it is laghu. In matra (mora) counting, laghu = 1 and guru = 2.
Pingala grouped syllables in threes called ganas. Since each syllable can be light or heavy, there are 2 × 2 × 2 = 8 ganas, remembered by the mnemonic "ya-mā-tā-rā-ja-bhā-na-sa-la-gāḥ" (ya, ma, ta, ra, ja, bha, na, sa ganas, plus single laghu and guru).
Vedic metres are counted by syllables:
- Gayatri: 3 lines of 8 syllables = 24
- Anushtubh: 4 lines of 8 = 32 (the common shloka is a form of anushtubh)
- Trishtubh: 4 lines of 11 = 44
- Jagati: 4 lines of 12 = 48
Classical metres are of two broad types: varnavritta (fixed pattern of syllables, such as Mandakranta or Vasantatilaka) and matravritta (fixed number of morae, such as Arya). Pingala also described methods for listing all possible patterns of a given length (prastara); the number of patterns for n syllables is 2ⁿ. A later commentator, Halayudha, explained a triangular arrangement (meru-prastara) of the kind now called Pascal's triangle.
Key points
- Laghu (1 matra), guru (2 matras).
- 8 ganas of 3 syllables.
- Gayatri 24, Anushtubh 32, Trishtubh 44, Jagati 48.
- Patterns of n syllables = 2ⁿ.
Exam tips
- Practise counting syllables and patterns; numerical questions are common.
Common mistakes
- Calling a short vowel before a single consonant guru — it stays laghu.