The Cethramtu Raanigheacht Mor is one of the simpler Irish poetic forms. I am not exactly sure how to pronounce this one, so I am not even going to try. Like most Irish poetic forms, there is a rhyming scheme to follow. They also use cywddydd (harmony of sound) and dunadh.

Here are the rules:

• Each stanza is made up of a quatrain that contains four lines. The poem can consist of as many quatrains as you wish.
• Each line should be only three syllables.
• The first line and third line of each quatrain are unrhymed.
• The second and fourth line of each quatrain rhyme.
• Use of cywddydd (harmony of sound).
• The final syllable, word, or line of the entire poem should be the same as the entire poem begins (the poetic term for this is dunadh)

Here’s the syllable/rhyming scheme shown in a way that I find easiest to understand:

xxx
xxa
xxx
xxa

What is cywddydd or harmony of sound? It is the use of following poetic devices:

Alliteration, repeating the same first letter or sound at the beginning of adjacent words
Consonance, recurring similar sounds, especially consonants
Assonance, repetition of the sound of a vowel