Each 16-syllable
hemistich (half-verse), of two 8-syllable
pādas, can take either a
pathyā ("normal") form or one of several
vipulā ("extended") forms. The form of the second
foot of the first
pāda (II.) limits the possible patterns the first foot (I.) may assume. The scheme below, given by Macdonell, shows his understanding of the form of the
śloka in the classical period of Sanskrit literature (4th–11th centuries CE): In poems of the intermediate period, such as the
Bhagavad Gita, a fourth
vipulā is found. This occurs 28 times in the Bhagavad Gita, that is, as often as the third
vipulā. When this
vipulā is used, there is a word-break (caesura) after the fourth syllable: :1. In both
pādas, in syllables 2–3, u u is not allowed. :2. In the second
pāda, in syllables 2–4, – u – is not allowed The
pathyā and
vipulā half-verses are arranged in the table above in order of frequency of occurrence. Out of 2579 half-verses taken from
Kalidasa,
Bharavi,
Magha, and
Bilhana, each of the four admissible forms of
śloka in this order claims the following share: 2289, 116, 89, 85; that is, 89% of the half-verses have the regular
pathyā form. The various
vipulās, in the order above, are known to scholars writing in English as the first, second, third and fourth
vipulā, or the
paeanic,
choriambic,
molossic, and
trochaic vipulā respectively. In Sanskrit writers, they are referred to as the
na-,
bha-,
ma-, and
ra-vipulā. Macdonell's chart given above is in fact too restrictive with regard the first four syllables in a
vipulā verse. For example, the first quarter verse of the
Rāmayaṇa (critical edition) contains a
na-vipulā and scans ⏑ – – – ⏑ ⏑ ⏑ – (
tapaḥsvādhyāyanirataṃ). Other examples are easy to find among classical poets, e.g.,
Rāmacarita 1.76
manyur dehāvadhir ayaṃ – – – – ⏑ ⏑ ⏑ –. In the ma-vipulā, a caesura is not obligatory after the fifth syllable, e.g.,
Śiśupālavadha 2.1a
yiyakṣamāṇenāhūtaḥ ⏑ – ⏑ – – – – –. Noteworthy is the avoidance of an iambic cadence in the first
pāda. By comparison, syllables 5–8 of any
pāda in the old Vedic
anuṣṭubh metre typically had the iambic ending u – u x (where "x" represents an
anceps syllable). Statistical studies examining the frequency of the
vipulās and the patterns in the earlier part of the
pāda have been carried out to try to establish the preferences of various authors for different metrical patterns. It is believed that this may help to establish relative dates for the poems, and to identify interpolated passages. The Kannada
śloka described by Nāgavarma I in his
Chandombudhi allows any light (
laghu) or heavy (
guru) syllable in the first four and the eighth syllable, requires a light and heavy syllable in the fifth and sixth respectively, and alternates the seventh as long in odd-numbered
pādas and short in even-numbered ones. The eighth syllable is often heavy, but it is not mandatory. Nāgavarma does say, however, that the seventh syllable may be also long across all four
pādas, citing the practice of earlier poets. ==Examples==