Hunminjeongeum (Korean: ?; Hanja: ?; lit. The Correct/Proper Sounds for the Instruction of the People) is a document describing an entirely new and native script for the Korean language. The script was initially named after the publication, but later came to be known as hangul. It was created so that the common people illiterate in hanja could accurately and easily read and write the Korean language. It was announced in Volume 102 of the Annals of King Sejong, and its formal supposed publication date, October 9th, 1446, is now Hangul Day in South Korea. The Annals place its invention to the 25th year of Sejong's reign, corresponding to 1443-1444.
Before Hangul, the Korean alphabet, was created, Koreans used Chinese letters to record their words. Since Chinese language and Korean language share few similarities, borrowing Chinese characters proved to be inefficient to reflect the spoken language.  In addition, the Ming Dynasty had just come to power in China at the time when King Sejong was inventing Hangul, which changed the pronunciation of Chinese characters making it harder for Koreans to learn the new standard pronunciation to record their words. The literacy level also stayed high since reading and learning Chinese characters were restricted to the ordinary people and were generally used in official documents by the ruling class. The ruling class took advantage of this and learning the Chinese characters became a symbol of power and privilege. In order to make written language more accessible for common people, King Sejong started creating Hangul secretly, since the ruling class would be appalled by the news. Although it is widely assumed that King Sejong ordered the Hall of Worthies to invent Hangul, contemporary records such as the Veritable Records of King Sejong and Jeong Inji's preface to the Hunminjeongeum Haerye emphasize that he invented it himself.
Hangul was personally created by Sejong the Great, the fourth king of the Joseon dynasty, and revealed by him in 1443. This is stated in Book 113 of The Annals of King Sejong (Sejongsillok) on the 9th month and the 28th year of reign of King Sejong and at the end of An Illustrated Explanation of Hunminjeongeum (Hunminjeongeum Haeryebon).Afterward, King Sejong wrote the preface to the Hunminjeongeum, explaining the origin and purpose of Hangul and providing brief examples and explanations, and then tasked the Hall of Worthies to write detailed examples and explanations. The head of the Hall of Worthies, Jeong In-ji, was responsible for compiling the Hunminjeongeum. The Hunminjeongeum was published and promulgated to the public in 1446.The writing system is referred to as "Hangul" today but was originally named as Hunminjeongeum by King Sejong. "Hunmin" and "Jeongeum" are respective words that each indicate "to teach the people" and "proper sounds." Together Hunminjeongeum means "correct sounds for the instruction of the people"
The publication is written in Classical Chinese and contains a preface, the alphabet letters (jamo), and brief descriptions of their corresponding sounds. It is later supplemented by a longer document called Hunminjeongeum Haerye that is designated as a national treasure No. 70. To distinguish it from its supplement, Hunminjeongeum is sometimes called the "Samples and Significance Edition of Hunminjeongeum" (?; ?).
The Classical Chinese (/hanmun) of the Hunminjeongeum has been partly translated into Middle Korean. This translation is found together with Worinseokbo, and is called the Hunminjeongeum Eonhaebon.
The first paragraph of the document reveals King Sejong's motivation for creating hangul:
Because the speech of this country is different from that of China, it [the spoken language] does not match the [Chinese] letters. Therefore, even if the ignorant want to communicate, many of them in the end cannot state their concerns. Saddened by this, I have [had] 28 letters newly made. It is my wish that all the people may easily learn these letters and that [they] be convenient for daily use.
The language of [our] people is different from that of the nation of China and thus cannot be expressed by the written language of Chinese people. Because of this reason, the cries of illiterate peasants are not properly understood by the many [in the position of privilege]. I [feel the plight of the peasants and the difficulties faced by the public servants and] am saddened by the situation.
Therefore, twenty eight [written] characters have been newly created. [My desire is] such that, each [Korean] person may become familiar [with the newly created written language of Korean] and use them daily in an intuitive way.
The manuscript of the original Hunminjeongeum has two versions: