Until the contemporary period, Korean documents, history, literature and records were written primarily in Literary Chinese using Hanja as its primary script.

According to the Book of Liang, the people of Silla did not have writing in the first half of the 6th century but this may have been only referring to agreements and contracts, represented by notches on wood.

[13] Some western writers claimed that knowledge of Chinese entered Korea with the spread of Buddhism, which occurred around the 4th century.

Passage of the gwageo required the thorough ability to read, interpret and compose passages of works such as the Analects (논어; 論語; Non-eo), Great Learning (대학; 大學; Daehak), Doctrine of the Mean (중용; 中庸; Jung-yong), Mencius (맹자; 孟子; Maengja), Classic of Poetry (시경; 詩經; Sigyeong), Book of Documents (서경; 書經; Seogyeong), Classic of Changes (역경; 易經; Yeokgyeong), Spring and Autumn Annals (춘추; 春秋; Chunchu) and Book of Rites (예기; 禮記; Yegi).

Other important works include Sūnzǐ's Art of War (손자병법; 孫子兵法; Sonja Byeongbeop), Selections of Refined Literature (문선; 文選; Munseon), etc.

The craftsmen and scholars of Baekje were renowned in Japan, and were eagerly sought as teachers due to their proficiency in hanmun.

The Chinese language, however, was quite different from the Korean language, consisting of terse, often monosyllabic words with a strictly analytic, SVO structure in stark contrast to the generally polysyllabic, very synthetic, SOV structure, with various grammatical endings that encoded person, levels of politeness and case found in Korean.

Chinese texts were broken into meaningful blocks, and in the spaces were inserted hanja used to represent the sound of native Korean grammatical endings.

As literary Chinese was very terse, leaving much to be understood from context, insertion of occasional verbs and grammatical markers helped to clarify the meaning.

For instance, the hanja '爲' was used for its native Korean gloss whereas '尼' was used for its Sino-Korean pronunciation, and combined into '爲尼' and read hani (하니), 'to do (and so).

Although it was developed by scholars of the early Goryeo Kingdom (918–1392), gugyeol was of particular importance during the Joseon period, extending into the first decade of the twentieth century, since all civil servants were required to be able to read, translate and interpret Confucian texts and commentaries.

[16] The first attempt at transcribing Korean in hanja was the idu (이두; 吏讀), or 'official reading,' system that began to appear after 500 AD.

[17][16] Hanja were the sole means of writing Korean until King Sejong the Great invented and tried promoting Hangul in the 15th century.

Mixed script could be commonly found in non-fiction writing, news papers, etc., until the enacting of President Park Chung Hee's 5 Year Plan for Hangul Exclusivity (한글전용 5개년 계획안; 한글專用 5個年 計劃案; Hangeuljeonyong Ogaenyeon Gyehoegan)[18] in 1968 banned the use and teaching of Hanja in public schools, as well as forbade its use in the military, with the goal of eliminating Hanja in writing by 1972 through legislative and executive means.

[19] With further adoption, during the 1970s, even when Hanja and mixed script were still used widely in society both as a writing system and as a style option, Koreans mostly gave up on mixed script at least in government documents and memorandums;[20] The use of Hanja in type hindered the speed of writing and printing compared to only-Hangul usage, especially after the advent of the Sebeolsik layout (세벌식 자판; 세벌式 字板).

In 1999, the government of Kim Dae-jung actively promoted Hanja by placing it on signs on the road, at bus stops, and in subways.

Where Hanja is now very rarely used and is almost only used for abbreviations in newspaper headlines (e.g. 中 for China, 韓 for Korea, 美 for the United States, 日 for Japan, etc.

), for clarification in text where a word might be confused for another due to homophones (e.g. 이 사장 (李 社長) vs. 이사장 (理事長)), or for stylistic use such as the 辛 (신라면; 辛拉麵) used on Shin Ramyŏn packaging.

Since June 1949, Hanja has not officially been used in North Korea, and, in addition, most texts are now commonly written horizontally instead of vertically.

[28] Kim Il Sung had earlier called for a gradual elimination of the use of Hanja,[29] but by the 1960s, he had reversed his stance; he was quoted as saying in 1966, "While we should use as few Sinitic terms as possible, students must be exposed to the necessary Chinese characters and taught how to write them.

Hanja are often also used as a form of shorthand in newspaper headlines, advertisements, and on signs, for example the banner at the funeral for the sailors lost in the sinking of ROKS Cheonan (PCC-772).

[33] In South Korea, Hanja are used most frequently in ancient literature, legal documents, and scholarly monographs, where they often appear without the equivalent Hangul spelling.

In mass-circulation books and magazines, Hanja are generally used rarely, and only to gloss words already spelled in Hangul when the meaning is ambiguous.

Aside from academic usage, Hanja are often used for advertising or decorative purposes in South Korea, and appear frequently in athletic events and cultural parades, packaging and labeling, dictionaries and atlases.

[35] In contrast, North Korea eliminated the use of Hanja even in academic publications by 1949 on the orders of Kim Il Sung, a situation that has since remained unchanged.

An example is the word 수도 (sudo), which may have meanings such as:[36] Hanja dictionaries for specialist usage – Jajeon (자전; 字典) or Okpyeon (옥편; 玉篇) – are organized by radical (the traditional Chinese method of classifying characters).

[5] Due to standardization efforts during Goryeo and Joseon eras, native Korean placenames were converted to Hanja, and most names used today are Hanja-based.

[37] For the traditional creative arts such as calligraphy and painting, a knowledge of Hanja is needed to write and understand the various scripts and inscriptions, as is the same in China and Japan.

Further examples include 巭 (부 bu), 頉 (탈 tal), 䭏 (편 pyeon), 哛 (뿐 ppun), and 椧 (명 myeong).

Other examples include 사람 인 (saram-in) for 人 'person/people', 클 대 (keul-dae) for 大 'big/large/great', 작을 소 (jageul-so) for 小 'small/little', 아래 하 (arae-ha) for 下 'underneath/below/low', 아비 부 (abi-bu) for 父 'father', and 나라이름 한 (naraireum-han) for 韓 'Han/Korea'.