Korean poetry is poetry performed or written in the Korean language or by Korean people. Traditional Korean poetry is often sung in performance. Until the 20th century, much of Korean poetry was written in Hanja and later Hangul.
The performance of oral songs in the religious life of the ancient Korean people is vivildy recorded in Chinese dynastic histories. At state assemblies the chief ritualist would tell the story of the divine origin of the founder, as evinced by foundation myths, and his extraordinary deeds in war and peace. Recited narrative was interspersed with primal songs (norae) that not only welcomed, entertained, and sent off gods and spirits. Thus orality and performance were significant features of vernacular poetry in ancient Korea.
A famous surviving example dates to 17 BC, Yuri's Song of Yellow Birds (Hwangjoga, 황조가/黃鳥歌). Some later Korean poetry followed the style of Tang lyric poetry such as the shi poetry form. Notable Korean poetry began to flourish during the Goryeo period (starting in 935). Collections were rarely printed.
Sijo, Korea's favorite poetic genre, is often traced to seonbi scholars of the 11th century, but its roots, too, are in those earlier forms. The earliest surviving poem of the sijo genre is from the 4th century. Its greatest flowering occurred in the 16th and 17th centuries under the Joseon Dynasty.
Hyangga poetry refers to vernacular Korean poetry which transcribed Korean sounds using Hanja (similar to the idu system, the hyangga style of transcription is called hyangch'al) and is characteristic of the literature of Unified Silla. It is one of the first uniquely Korean forms of poetry. The Goryeo period Samguk Yusa contains 14 poems that have been preserved to the present day. These are thought to have been taken by Ilyon (compiler of Samguk Yusa) from an anthology called the Samdaemok(삼대목/三代目) which was completed during the Shilla period, in 888 (according to Samguk Sagi), but is no longer extant today. This lost anthology is thought to have contained approximately 1,000 hyangga. Eleven poems from the later Goryeo Dynasty Gyunyeojeon (균여전/均如傳), characterized by the same style, have also been preserved.
Hyangga are characterized by a number of formal rules. The poems may consist of four, eight or ten lines. The ten-line poems are the most developed, structured into three sections with four, four, and two lines respectively. Many of the ten-line poems were written by Buddhist monks. The extent of the Shilla hwarang's role in the development and flourishing of the hyangga genre is a subject of much scholarly interest.
Goryeo songs 
The Goryeo period was marked by a growing use of Hanja. Hyangga largely disappeared as a form of Korean literature, and "Goryeo songs" (Goryeo gayo) became more popular. Most of the Goryeo songs were transmitted orally and many survived into the Joseon period, when some of them were written down using hangul.
The poetic form of the Goryeo songs is known as byeolgok. There are two distinct forms: dallyeonche (단련체) and yeonjanche (연잔체). The former is a short form, whereas the latter is a more extended form. The Goryeo songs are characterized by their lack of clear form, and by their increased length. Most are direct in their nature, and cover aspects of common life.
During the Joseon dynasty,a three-line poetry, called sijo, became more popular and reached its apex in the late 18th century. Sijo is a modern term for what was then called dan-ga (literally, "short song").
The sijo having a strong foundation in nature in a short profound structure. Bucolic, metaphysical and astronomical themes are often explored. The lines average 14-16 syllables, for a total of 44-46. There is a pause in the middle of each line, so in English they are sometimes printed in six lines instead of three. Most poets follow these guidelines very closely although there are longer examples. The most famous example is possibly this piece by Yun Seondo:
- You ask how many friends I have? Water and stone, bamboo and pine.
- The moon rising over the eastern hill is a joyful comrade.
- Besides these five companions, what other pleasure should I ask?
Yun Seondo (1587–1671) also wrote a famous collection of forty sijo of the changing seasons through the eyes of a fisherman.
Either narrative or thematic, this lyric verse introduces a situation or problem in line 1, development (called a turn) in line 2, and a strong conclusion beginning with a surprise (a twist) in line 3, which resolves tensions or questions raised by the other lines and provides a memorable ending.
Sijo is, first and foremost, a song. This lyric pattern gained popularity in royal courts amongst the yangban as a vehicle for religious or philosophical expression, but a parallel tradition arose among the commoners. Sijo were sung or chanted with musical accompaniment, and this tradition survives. The word originally referred only to the music, but it has come to be identified with the lyrics.
Gasa is a form of verse, although its content can include more than the expression of individual sentiment, such as moral admonitions. Gasa is a simple form of verse, with twinned feet of three or four syllables each. Some regard gasa a form of essay. Common themes in gasa were nature, the virtues of gentlemen, or love between man and woman.
The form had first emerged during the Goryeo period., and was popular during the Joseon Dynasty. They were commonly sung, and were popular among yangban women. Jeong Cheol, a poet of the 16th century, is regarded as having perfected the form, which consisted of parallel lines, each broken into two.
Modern poetry 
There were attempts at introducing imagist and modern poetry methods particularly in translations of early American moderns such as Ezra Pound and T. S. Eliot in the early 20th century. In the early Republic period (starting in 1953 after the Korean War), patriotic works were very successful.
Lyrical poetry dominated from the 1970s onwards. Poetry is quite popular in 21st century Korea, both in terms of number of works published and lay writing.
A corpus of modern Korean poetry is being compiled. The work provides linguistic information on 10,300 original Korean poems.
See also 
- The Columbia anthology of traditional Korean poetry By Peter H. Lee
- Kim Byong-sun, 2002, "The Present Conditions and Tasks in Constructing the Database of Korean Literary Materials Centering on the Korean Poetry Corpus," The Review of Korean Studies 8 (4):105-140. http://review.aks.ac.kr/AttachedFiles/02기획논문_4김병선.pdf