In most metres a verse (gàthà) is made up of 4 lines (pàda), though sometimes we find verses with 6 lines, or more rarely 5. Pàëi metres are constructed according to the amount of syllables or measures there are in the line, and the patterns that are made through the alternation of the light and heavy syllables.

The metres can be divided into two main types according to their method of construction, in outline they are:

We can usefully divide these into two further groups, according to the specific basis for their construction, numbers 1 and 4 below are syllabic metres, further divided according to whether their syllables are flexible or fixed; numbers 2 and 3 are types of measure metres, according to whether they have been further organized into bars or not. We then have four main groups:

In the flexible syllabic metres it is the number of syllables that make up a line that is the organizing principle, e.g. Siloka has 8 syllables to the line, Tuññhubha 11, & Jagatã 12. Variations are allowed in regard to the weight of a numbers of the syllables in these metres (the various patterns that can occur are discussed in the descriptions that follow).

In the bar metres a secondary organising principle is employed over and above that of counting the measures, which is to organize the syllables into bars, normally of 4 measures to the bar. e.g Ariya has 16 bars, with 30 measures in its 1st line, and 27 in the second; Gãti has 16 bars, with 30 measures in both lines (how these figures are arrived at will be explained below).

In the fixed metres virtually all of the syllables in the lines are of fixed quantity, with normally only the weight of the beginning and end syllables being variable, e.g. Upajàti is a fixed form of the Tuññhubha metre, having 11 syllables to the line; Vaüsaññhà is a fixed form of Jagatã, having 12 syllables to the line.

After this brief outline of the different structural principles involved we can examine the metres in more depth.

In these the line length is determined by the number of syllables there are in a line, e.g. Siloka normally has 8; Tuññhubha 11; Jagatã 12. These metres have a more or less fixed cadence (i.e. the closing rhythm of a line), but allow a greater freedom in the rest of the line, in which they differ from vaõõacchandas type 2. The syllabic metres are the most common type found in the canon.

The most important and prevalent metre in canonical Pàëi is the Siloka, which has a great deal of flexibility, and seems to be equally well adapted to aphorism, question & answer, narrative, and epic.

A Siloka verse normally consists of 4 lines (sometimes 6, rarely 5) with 8 syllables to the line, organised in dissimilar pairs which are repeated to make up a verse (note that owing to resolution sometimes a Siloka line may contain 9 syllables).

Here is an analysis of the pathyà (normal) structure of the Siloka:

In the odd lines 7 variations (vipulà) occur, besides the normal structure, they are:

There is normally a caesura (word break) after the fifth syllable in the mavipulà, and after the fourth syllable in the ravipulà.

if the caesura (word break) occurs after the fourth syllable, it is ravipulà:

if the caesura occurs after the 5th syllable, it is pathyà:

The Siloka metre in the canon can be divided roughly into two periods, the early and the late, according to whether the Anuññhubha variation occurs in the prior lines, or whether it is normally avoided. In the early period the pathyà accounts for about 60% or more of the prior lines, and the Anuññhubha at that time is the most important variation accounting for about 15%. As the metre comes closer to its classical form in the later part of the canon the Anuññhubha occurs only sporadically, and the pathyà greatly predominates, sometimes accounting for as much as 85% of all the lines (for more on the development of the Siloka, see the Appendix).

An interesting comparison is afforded between the early Siloka of the questions and answers in Pàràyanavagga of Suttanipàta, and the late Siloka of the Introductory Verses (Vatthugàthà). We may note here that in Hemakamàõavàpucchà (Sn V:8) (vs 1084 ff) we may have a case of the Anuññhubha being used as an independent metre in the canon, but as it is only 4 vs long it is too short to be sure.

Early Siloka from Jatukaõõãmàõavapucchà (Sn V: 12) (vs 1098-99):

Late Siloka (Sn V vs 1-3) (vs 976-978), narrative style:

As the variations that occur in the one also occur in the other, we can take the two metres together for description.

Tuññhubha normally has 11 syllables to the line, and is defined thus:

Jagatã is similar, but has an extra light syllable in penultimate position, giving a line of 12 syllables, thus:

Sometimes an extended form is produced by resolution at the first syllable, which then gives a line of 12 (13) syllables - note that the pattern of the cadence will help identify the metre in these cases.

Example of early Tuññhubha from Guhaññhakasutta (Sn IV: 2) (vs 776-779):

Mixed Tuññhubhajagatã, from Ratanasutta (Khp 6:8):

Extended Tuññhubha, from Nàlakasutta (Sn III: 11) (vs 679-680):

These are the fixed metres in the canon that have been derived from Tuññhubha and Jagatã, their profile looks like this:

i) Upajàti (from Tuññhubha):

ii) Vaüsaññhà (from Jagatã):

As can be seen these are the "normal" forms of their respective metres, but now allowing only little flexibility.

iii) Rucirà (from Jagatã, with resolution of the 5th syllable, giving a 13 syllable line):

Examples: Upajàti and Vaüsaññhà are used to great effect, both mixed and independently in Tàlaputta's gàthàs Th 1091-1145. Vaüsaññhà and Rucirà both appear as independent metres in Lakkhaõasuttanta DN.30 (see 2.24)

Example Upajàti/Vaüsaññhà, Th 1091-2:

Rucirà from Lakkhaõasuttanta (D. 30. 2. 9):