section_path: Vocabulary and adaptation/Korean
section_name: Korean
paragraph_text: Korean
  
  In Korean, Chinese characters are known as hanja. Literary Chinese may have been written in Korea as early as the 2nd century BCE. During the Three Kingdoms period (57 BCE – 668 CE), characters were also used to write idu, a form of Korean-language literature that mostly made use of Sino-Korean vocabulary. During the Goryeo period (918–1392), Korean writers developed a system of phonetic annotations for Literary Chinese called gugyeol, comparable to kundoku in Japan, though it only entered widespread use during the later Joseon period (1392–1897). While the hangul alphabet was invented by the Joseon king Sejong (r. 1418–1450) in 1443, it was not adopted by the Korean literati and was relegated to use in glosses for Literary Chinese texts until the late 19th century.
  
  Much of the Korean lexicon consists of Chinese loanwords, especially technical and academic vocabulary. While hanja were usually only used to write this Sino-Korean vocabulary, there is evidence that vernacular readings were sometimes used. Compared to the other written vernaculars, very few characters were invented to write Korean words; these are called gukja. During the late 19th and early 20th centuries, Korean was written either using a mixed script of hangul and hanja, or only using hangul. Following the end of the Empire of Japan 's occupation of Korea in 1945, the total replacement of hanja with hangul was advocated throughout the country as part of a broader "purification movement" of the national language and culture. However, due to the lack of tones in spoken Korean, there are many Sino-Korean words that are homophones with identical hangul spellings. For example, the phonetic dictionary entry for 기사 (gisa) yields more than 30 different entries. This ambiguity had historically been resolved by also including the associated hanja. While still sometimes used for Sino-Korean vocabulary, it is much rarer for native Korean words to be written using hanja. When learning new characters, Korean students are instructed to associate each one with both its Sino-Korean pronunciation, as well as a native Korean synonym. Examples include: