A Sijo is a type of poem that has three lines containing fourteen to sixteen lines each. The Sijo is a poem of Korean descent where each line of the poem having its own role. The first line is used in order to introduce the theme or topic of the poem. In the second line is meant to delve deeper, give more information about the theme that was introduced in the first line. It's meant to change or agree with and give detail on what the poem is about. The last line of a Sijo poem is the conclusion line. It takes the information from the second line about the topic from the first line and ends it in a way that is both beautiful and satisfying, or challenging depending on the poet. The ending line is not meant to be predictable, in fact, it's meant to twist what you know so that it is unexpected and enjoyable. A Sijo was originally meant to be sung so each line should have its own natural break.
Sijo is the classic form of unrhymed poetry in Korea. Sijo have three long lines. Each line varies between 14 and 16 syllables, with the middle line often the longest. The first line states a theme, the second line counters it, and the third line resolves the poem.
Example
I will break the back of this long, midwinter night,
Folding it double, cold beneath my spring quilt,
That I may draw out the night, should my love return.