Chữ Nôm (𡨸喃, IPA: [t͡ɕɨ˦ˀ˥ nom˧˧]) is a logographic writing system formerly used to write the Vietnamese language. It uses Chinese characters (chữ Hán) to represent Sino-Vietnamese vocabulary and some native Vietnamese words, with other words represented by new characters created using a variety of methods, including phono-semantic compounds. This composite script was therefore highly complex and was accessible to less than five percent of the Vietnamese population who had mastered written Chinese.
 Although formal writing in Vietnam was done in classical Chinese until the early 20th century (except for two brief interludes), chữ Nôm was widely used between the 15th and 19th centuries by the Vietnamese cultured elite for popular works in the vernacular, many in verse. One of the best-known pieces of Vietnamese literature, The Tale of Kiều, was written in chữ Nôm by Nguyễn Du.
 The Vietnamese alphabet created by Portuguese Jesuit missionaries, with the earliest known usage occurring in the 17th century, replaced chữ Nôm as the preferred way to record Vietnamese literature from the 1920s. While Chinese characters are still used for decorative, historic and ceremonial value, chữ Nôm has fallen out of mainstream use in modern Vietnam. In the 21st century, chữ Nôm is being used in Vietnam for historical and liturgical purposes. The Institute of Hán-Nôm Studies at Hanoi is the main research centre for pre-modern texts from Vietnam, both Chinese-language texts written in Chinese characters (chữ Hán) and Vietnamese-language texts in chữ Nôm.
 The Vietnamese word chữ 'character' is derived from the Middle Chinese word dziH 字, meaning '[Chinese] character'. The word Nôm 'Southern' is derived from the Middle Chinese word nom 南, meaning 'south'. It could also be based on the dialectal pronunciation from the South Central dialects (most notably in the name of province of Quảng Nam, known locally as Quảng Nôm).
 There are many ways to write the name chữ Nôm in chữ Nôm characters. The word chữ may be written as 字, 𫳘(⿰字宁), 𡨸, 𫿰(⿰字文), 𡦂(⿰字字), 𲂯(⿰貝字), 𱚂(⿱字渚), or 宁, while Nôm is written as 喃.
 Chữ Nôm is the logographic writing system of the Vietnamese language. It is based on the Chinese writing system but adds a large number of new characters to make it fit the Vietnamese language. Common historical terms for chữ Nôm were Quốc Âm (國音, 'national sound') and Quốc ngữ (國語, 'national language').
 In Vietnamese, Chinese characters are called chữ Hán (𡨸漢 'Han characters'), chữ Nho (𡨸儒 'Confucian characters', due to the connection with Confucianism) and uncommonly as Hán tự (漢字 'Han characters'). Hán văn (漢文) refers literature written in Literary Chinese.
 The term Hán Nôm (漢喃 'Han and chữ Nôm characters') in Vietnamese designates the whole body of premodern written materials from Vietnam, either written in Chinese (chữ Hán) or in Vietnamese (chữ Nôm). Hán and Nôm could also be found in the same document side by side, for example, in the case of translations of books on Chinese medicine. The Buddhist history Cổ Châu Pháp Vân phật bản hạnh ngữ lục (1752) gives the story of early Buddhism in Vietnam both in Hán script and in a parallel Nôm translation. The Jesuit Girolamo Maiorica (1605–1656) had also used parallel Hán and Nôm texts.
 The term chữ Quốc ngữ (𡨸國語 'national language script') refers to the Vietnamese alphabet in current use, but was used to refer to chữ Nôm before the Vietnamese alphabet was widely used.
 Chinese characters were introduced to Vietnam after the Han dynasty conquered Nanyue in 111 BC.  Independence was achieved after the Battle of Bạch Đằng in 938, but Literary Chinese was adopted for official purposes in 1010. For most of the period up to the early 20th century, formal writing was indistinguishable from contemporaneous classical Chinese works produced in China, Korea, and Japan.
 Vietnamese scholars were thus intimately familiar with Chinese writing.  In order to record their native language, they applied the structural principles of Chinese characters to develop chữ Nôm.  The new script was mostly used to record folk songs and for other popular literature.  Vietnamese written in chữ Nôm briefly replaced Chinese for official purposes under the Hồ dynasty (1400–1407) and under the Tây Sơn (1778–1802), but in both cases this was swiftly reversed.
 The use of Chinese characters to transcribe the Vietnamese language can be traced to an inscription with the two characters "布蓋", as part of the posthumous title of Phùng Hưng, a national hero who succeeded in briefly expelling the Chinese in the late 8th century. The two characters have literal Chinese meanings 'cloth' and 'cover', which make no sense in this context.  They have thus been interpreted as a phonetic transcription, via their Middle Chinese pronunciations buH kajH, of a Vietnamese phrase, either vua cái 'great king', or bố cái 'father and mother' (of the people).
 After Vietnam established its independence from China in the 10th century, Đinh Bộ Lĩnh (r. 968–979), the founder of the Đinh dynasty, named the country Đại Cồ Việt 大瞿越. The first and third Chinese characters mean 'great' and 'Viet'. The second character was often used to transcribe non-Chinese terms and names phonetically. In this context, cồ is an obsolete Vietnamese word for 'big'.
 The oldest surviving Nom inscription, dating from 1210, is a list naming 21 people and villages on a stele at the Tự Già Báo Ân pagoda in Tháp Miếu village (Mê Linh District, Hanoi). Another stele at Hộ Thành Sơn in Ninh Bình Province (1343) lists 20 villages.
 Trần Nhân Tông (r. 1278–1293) ordered that Nôm be used to communicate his proclamations to the people.
The first literary writing in Vietnamese is said to have been an incantation in verse composed in 1282 by the Minister of Justice Nguyễn Thuyên and thrown into the Red River to expel a menacing crocodile.
Four poems written in Nom from the Tran dynasty, two by Trần Nhân Tông and one each by Huyền Quang and Mạc Đĩnh Chi, were collected and published in 1805.
 The Nôm text Phật thuyết Đại báo phụ mẫu ân trọng kinh ('Sūtra explained by the Buddha on the Great Repayment of the Heavy Debt to Parents') was printed around 1730, but conspicuously avoids the character 利 lợi, suggesting that it was written (or copied) during the reign of Lê Lợi (1428–1433).
Based on archaic features of the text compared with the Tran dynasty poems, including an exceptional number of words with initial consonant clusters written with pairs of characters, some scholars suggest that it is a copy of an earlier original, perhaps as early as the 12th century.
 During the seven years of the Hồ dynasty (1400–07) Classical Chinese was discouraged in favor of vernacular Vietnamese written in Nôm, which became the official script. The emperor Hồ Quý Ly even ordered the translation of the Book of Documents into Nôm and pushed for reinterpretation of Confucian thoughts in his book Minh đạo. These efforts were reversed with the fall of the Hồ and Chinese conquest of 1407, lasting twenty years, during which use of the vernacular language and demotic script were suppressed.
 During the Ming dynasty occupation of Vietnam, chữ Nôm printing blocks, texts and inscriptions were thoroughly destroyed; as a result the earliest surviving texts of chữ Nôm post-date the occupation.
 Among the earlier works in Nôm of this era are the writings of Nguyễn Trãi (1380–1442). The corpus of Nôm writings grew over time as did more scholarly compilations of the script itself. Trịnh Thị Ngọc Trúc [vi], consort of King Lê Thần Tông, is generally given credit for Chỉ nam ngọc âm giải nghĩa [vi] (指南玉音解義; 'guide to Southern Jade sounds: explanations and meanings'), a 24,000-character bilingual Hán-to-Nôm dictionary compiled between the 15th and 18th centuries, most likely in 1641 or 1761.
 While almost all official writings and documents continued to be written in classical Chinese until the early 20th century, Nôm was the preferred script for literary compositions of the cultural elites. Nôm reached its golden period with the Nguyễn dynasty in the 19th century as it became a vehicle for diverse genres, from novels to theatrical pieces, and instructional manuals. Although it was prohibited during the reign of Minh Mạng (1820–1840), apogees of Vietnamese literature emerged with Nguyễn Du's The Tale of Kiều and Hồ Xuân Hương's poetry. Although literacy in premodern Vietnam was limited to just 3 to 5 percent of the population, nearly every village had someone who could read Nôm aloud for the benefit of other villagers. Thus these Nôm works circulated orally in the villages, making it accessible even to the illiterates.
 Chữ Nôm was the dominant script in Vietnamese Catholic literature until the late 19th century. In 1838, Jean-Louis Taberd compiled a Nôm dictionary, helping with the standardization of the script.
 The reformist Catholic scholar Nguyễn Trường Tộ presented the Emperor Tự Đức with a series of unsuccessful petitions (written in classical Chinese, like all court documents) proposing reforms in several areas of government and society. His petition Tế cấp bát điều (濟急八條 'Eight urgent matters', 1867), includes proposals on education, including a section entitled Xin khoan dung quốc âm ('Please tolerate the national voice'). He proposed to replace classical Chinese with Vietnamese written using a script based on Chinese characters that he called Quốc âm Hán tự (國音漢字 'Han characters with national pronunciations'), though he described this as a new creation, and did not mention chữ Nôm.
 From the latter half of the 19th century onwards, the French colonial authorities discouraged or simply banned the use of classical Chinese, and promoted the use of the Vietnamese alphabet, which they viewed as a stepping stone toward learning French. Language reform movements in other Asian nations stimulated Vietnamese interest in the subject. Following the Russo-Japanese War of 1905, Japan was increasingly cited as a model for modernization. The Confucian education system was compared unfavourably to the Japanese system of public education. According to a polemic by writer Phan Châu Trinh, "so-called Confucian scholars" lacked knowledge of the modern world, as well as real understanding of Han literature. Their degrees showed only that they had learned how to write characters, he claimed.
 The popularity of Hanoi's short-lived Tonkin Free School suggested that broad reform was possible. In 1910, the colonial school system adopted a "Franco-Vietnamese curriculum", which emphasized French and alphabetic Vietnamese. The teaching of Chinese characters was discontinued in 1917. On December 28, 1918, Emperor Khải Định declared that the traditional writing system no longer had official status. The traditional Civil Service Examination, which emphasized the command of classical Chinese, was dismantled in 1915 in Tonkin and was given for the last time at the imperial capital of Huế on January 4, 1919. The examination system, and the education system based on it, had been in effect for almost 900 years. 
 The decline of the Chinese script also led to the decline of chữ Nôm given that Nôm and Chinese characters are so intimately connected. After the First World War, chữ Nôm gradually died out as the Vietnamese alphabet grew more and popular. In an article published in 1935 (based on a lecture given in 1925), Georges Cordier estimated that 70% of literate persons knew the alphabet, 20% knew chữ Nôm and 10% knew Chinese characters.
However, estimates of the rate of literacy in the late 1930s range from 5% to 20%.
By 1953, literacy (using the alphabet) had risen to 70%.
 The Gin people, descendants of 16th-century migrants from Vietnam to islands off Dongxing in southern China, now speak a form of Yue Chinese and Vietnamese, but their priests use songbooks and scriptures written in chữ Nôm in their ceremonies.
 Vietnamese is a tonal language, like Chinese, and has nearly 5,000 distinct syllables.
In chữ Nôm, each monosyllabic word of Vietnamese was represented by a character, either borrowed from Chinese or locally created.
The resulting system was even more difficult to use than the Chinese script.
 As an analytic language, Vietnamese was a better fit for a character-based script than Japanese and Korean, with their agglutinative morphology.
Partly for this reason, there was no development of a phonetic system that could be taught to the general public, like Japanese kana syllabary or the Korean hangul alphabet.
Moreover, most Vietnamese literati viewed Chinese as the proper medium of civilized writing, and had no interest in turning Nôm into a form of writing suitable for mass communication.
 Chữ Nôm has never been standardized. As a result, a Vietnamese word could be represented by several Nôm characters. For example, the very word chữ ('character', 'script'), a Chinese loanword, can be written as either 字 (Chinese character), 𡦂 (Vietnamese-only compound-semantic character) or 𡨸 (Vietnamese-only semantic-phonetic character). For another example, the word giữa ('middle'; 'in between') can be written either as 𡨌 (⿰守中) or 𫡉 (⿰字中). Both characters were invented for Vietnamese and have a semantic-phonetic structure, the difference being the phonetic indicator (守 vs. 字).
 Another example of a Vietnamese word that is represented by several Nôm characters is the word for moon, trăng. It can be represented by a Chinese character that is phonetically similar to trăng, 菱 (lăng), a chữ Nôm character, 𢁋 (⿱巴陵) which is composed of two phonetic components 巴 (ba) and 陵 (lăng) for the Middle Vietnamese blăng, or a chữ Nôm character, 𦝄 (⿰月夌) composed of a phonetic component 夌 (lăng) and a semantic component meaning 月 ('moon').
 Unmodified Chinese characters were used in chữ Nôm in three different ways.
 The first two categories are similar to the on and kun readings of Japanese kanji respectively. The third is similar to ateji, in which characters are used only for their sound value, or the Man'yōgana script that became the origin of hiragana and katakana.
 When a character would have two readings, a diacritic may be added to the character to indicate the "indigenous" reading. The two most common alternate reading diacritical marks are cá (𖿰), (a variant form of 个) and nháy (𖿱). Thus when 本 is meant to be read as vốn, it is written as 本𖿱, with a diacritic at the upper right corner.
 
Other alternate reading diacritical marks include tháu đấm (草𢶸) where a character is represented by a simplified variant with two points on either side of the character.  In contrast to the few hundred Japanese kokuji (国字) and handful of Korean gukja (국자, 國字), which are mostly rarely used characters for indigenous natural phenomena, Vietnamese scribes created thousands of new characters, used throughout the language.
 As in the Chinese writing system, the most common kind of invented character in Nôm is the phono-semantic compound, made by combining two characters or components, one suggesting the word's meaning and the other its approximate sound. For example,
 A smaller group consists of semantic compound characters, which are composed of two Chinese characters representing words of similar meaning. For example, 𡗶 (giời or trời 'sky', 'heaven') is composed of 天 ('sky') and 上 ('upper').
 A few characters were obtained by modifying Chinese characters related either semantically or phonetically to the word to be represented. For example,
 As an example of the way chữ Nôm was used to record Vietnamese, the first two lines of the Tale of Kiều (1871 edition), written in the traditional six-eight form of Vietnamese verse, consist of 14 characters:
 𤾓 Trăm hundred 𢆥 năm year 𥪞 trong in 𡎝 cõi world 𠊛 người person 些 ta, our 𤾓 𢆥 𥪞 𡎝 𠊛 些 Trăm năm trong cõi người ta, hundred year in world person our A hundred years—in this life span on earth, 𡨸 Chữ word 才 tài talent 𡨸 chữ word 命 mệnh destiny 窖 khéo clever 𱺵 là to be 恄 ghét hate 饒 nhau. each other 𡨸 才 𡨸 命 窖 𱺵 恄 饒 Chữ tài chữ mệnh khéo là ghét nhau. word talent word destiny clever {to be} hate {each other} talent and destiny are apt to feud. In 1993, the Vietnamese government released an 8-bit coding standard for alphabetic Vietnamese (TCVN 5712:1993, or VSCII), as well as a 16-bit standard for Nôm (TCVN 5773:1993). This group of glyphs is referred to as "V0." In 1994, the Ideographic Rapporteur Group agreed to include Nôm characters as part of Unicode. A revised standard, TCVN 6909:2001, defines 9,299 glyphs. About half of these glyphs are specific to Vietnam. Nôm characters not already encoded were added to CJK Unified Ideographs Extension B. (These characters have five-digit hexadecimal code points. The characters that were encoded earlier have four-digit hex.)
 Characters were extracted from the following sources:
 The V2, V3, and V4 proposals were developed by a group at the Han-Nom Research Institute led by Nguyễn Quang Hồng. V4, developed in 2001, includes over 400 ideograms formerly used by the Tày people of northern Vietnam. This allows the Tày language to get its own registration code. V5 is a set of about 900 characters proposed in 2001. As these characters were already part of Unicode, the IRG concluded that they could not be edited and no Vietnamese code was added. (This is despite the fact that national codes were added retroactively for version 3.0 in 1999.) The Nôm Na Group, led by Ngô Thanh Nhàn, published a set of nearly 20,000 Nôm characters in 2005. This set includes both the characters proposed earlier and a large group of additional characters referred to as "V6". These are mainly Han characters from Trần Văn Kiệm's dictionary which were already assigned code points. Character readings were determined manually by Hồng's group, while Nhàn's group developed software for this purpose. The work of the two groups was integrated and published in 2008 as the Hán Nôm Coded Character Repertoire.
 The characters that do not exist in Chinese have Sino-Vietnamese readings that are based on the characters given in parentheses. The common character for càng (強) contains the radical 虫 (insects). This radical is added redundantly to create 𫋙, a rare variation shown in the chart above. The character 𫡯 (chàu) is specific to the Tày people. It has been part of the Unicode standard only since version 8.0 of June 2015, so there is still very little font and input method support for it. It is a variation of 朝, the corresponding character in Vietnamese.
 There are a number of software tools that can produce chữ Nôm characters simply by typing Vietnamese words in chữ quốc ngữ:
 Other entry methods:
 Fonts with a sufficient coverage of Chữ Nôm characters include Han-Nom Gothic, Han-Nom Minh, Han-Nom Ming, Han-Nom Kai, Nom Na Tong, STXiHei (Heiti TC), MingLiU plus MingLiU-ExtB, Han Nom A plus Han Nom B, FZKaiT-Extended plus FZKaiT-Extended(SIP), and Mojikyō fonts which require special software. The following web pages are collections of URLs from which Chữ Nôm capable fonts can be downloaded: