Ruba'i

In classical Persian poetry, the ruba'i is written as a four-line (or two-couplet / two-distich) poem, with a rhyme-scheme ${\displaystyle \mathrm{A}\mathrm{A}\mathrm{B}\mathrm{A}}$ or ${\displaystyle \mathrm{A}\mathrm{A}\mathrm{A}\mathrm{A}}$.

This is an example of a ruba'i from Rumi's Divan-e Shams:

Anwār-i Ṣalāḥ-i Dīn bar angēkhta bād

Dar dīda (w)u jān-i ʿāshiqān rēkhta bād

Har jān ki laṭīf gasht u az luṭf guzasht

Bā khāk-i Ṣalāḥ-i Dīn dar-āmēkhta bād

May the splendors of Salahuddin be roused,

And poured into the eyes and souls of the lovers.

May every soul that has become refined and has surpassed refinement

Be mingled with the dust of Salahuddin!

Metre

The usual metre of a Persian ruba'i, which is used for all four lines of the above quatrain by Rumi, is, as follows:

– – u u – u – u – – u u –

In the above scheme, quantitatively, "–" represents a long syllable, and "u" a short one. As variations of this scheme, any sequence of – u, except the final syllable of each line, can be replaced by a single "overlong" syllable, such as gēkh, tīf, luṭf in the poem above, containing either a long vowel followed by a consonant other than "n", or a short vowel followed by two consonants. An overlong syllable, as mentioned, can freely be substituted for the final syllable of the line, as with bād above.

Another variation, as a poetic licence rule, is that occasionally a sequence of two short syllables (u u) can be replaced by a single long one (–).

A third variation is to use the same metre as above, but with the sixth and seventh syllables reversed:

– – u u – – u u – – u u –