Modern Korean literature and all of the informal writing is now written entirely in Hangeul.

Korean Language The Korean writing system is known as Hangeul. Like its spoken form, Hangeul is heavily influenced by Chinese writing. It was widely used during the Chinese occupation of Northern Korea from 108 BC to 313 AD, roughly about 2,000 years ago. Koreans during that time started writing in Classical Chinese but then later devised three different systems.
The Hyangchal system used Chinese characters to represent all the sounds of Korean. It was used mainly for literature, most especially in poetry. The second system is the Gukyeol. The third is the Idu system and it is a combination of Chinese characters together with special symbols. These special symbols indicate grammatical markers and were used in official documents.
However, the Hangeul that we now know was invented in 1444 and promulgated in 1446 during the reign of fourth king of the Joseon Dynasty King, Sejong (r.1418-1450). The shapes of the characters, most especially the consonants, are based on the shape the mouth made when the corresponding sound is made. Like the Chinese, the direction of writing is also vertically from right to left. This is also the same in the practice of writing syllables in blocks. The alphabet was originally called Hunmin jeongeum. It has also been known as Eonmeun (vulgar script), as it was first used by the masses. Eventually, it was called Gukmeun (national writing). Hangeul, the modern name for the alphabet, was not coined until the Korean linguist Ju Si-gyeong came along. Although modern Korean literature and all of the informal writing is now written entirely in Hangeul, academic papers and official documents are more or less written in a mixture of Hangeul and Hanja (Chinese characters).

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