first made by the scientist
Chang Yŏngsil during the reign of
King Sejong 15th century The Joseon Dynasty under the reign of
Sejong the Great was Korea's greatest period of scientific advancement. In the first half of the 15th century, around 62 major accomplishments were made in various scientific fields. Of these, 29 came from Korea alone compared to 5 from China and 28 from the rest of the world. Under Sejong's new policy
Cheonmin (low-status) people such as
Chang Yŏngsil were allowed to work for the government. At a young age, Chang displayed talent as an inventor and engineer, creating machines to facilitate agricultural work. These included supervising the building of aqueducts and canals. Chang eventually was allowed to live at the royal palace, where he led a group of scientists to work on advancing Korea's science. Some of his inventions were an automated (self-striking)
water clock (the Jagyeokru) which worked by activating motions of wooden figures to indicate time visually (invented in 1434 by Chang), a subsequent more complicated water-clock with additional astronomical devices, and an improved model of the previous metal movable printing type created in the
Goryeo period. The new model was of even higher quality and was twice as fast. Other inventions were the
sight glass, and the
udometer. The highpoint of Korean astronomy was during the Joseon period, where men such as Chang created devices such as celestial globes which indicated the positions of the sun, moon, and the stars. Later celestial globes (Kyup'yo, 규표) were attuned to the seasonal variations. The apex of astronomical and calendarial advances under
King Sejong was the
Chiljeongsan, which compiled computations of the courses of the seven heavenly objects (five visible planets, the sun, and moon), developed in 1442. This work made it possible for scientists to calculate and accurately predict all the major heavenly phenomena, such as solar eclipses and other stellar movements.
Honcheonsigye is an astronomical clock created by
Song I-yeong in 1669. The clock has an armillary sphere with a diameter of . The sphere is activated by a working clock mechanism, showing the position of celestial objects at any given time. , the original version of
Hangul published by
King Sejong in 1444
Kangnido, a Korean-made map of the world was created in 1402 by
Kim Sa-hyeong (),
Yi Mu () and
Yi Hoe (). The map was created in the second year of the reign of
Taejong of Joseon. The map was made by combining Chinese, Korean and Japanese maps.
Hangul, the first and only
featural alphabet in current use for a
national language, was promulgated by Sejong in 1444. Hangul is an artificial writing system created based on science, and although about 600 years have passed since King Sejong created Hangul, North and South Korea still use Hangul. In addition, Hangul is one of the few unique writing systems in the world that does not originate from
Egyptian script or
Chinese character.
16th to 19th centuries The scientific and technological advance in the late Joseon Dynasty was less progressed than the early Joseon period. 16th-century court physician,
Heo Jun wrote a number of medical texts, his most significant achievement being
Dongeui Bogam, which is often noted as the defining text of
Traditional Korean medicine. The work spread to its East Asian neighbors,
China and
Japan, where it is still regarded as one of the classics of
Oriental medicine today. The first soft
ballistic vest,
Myunjebaegab, was invented in Joseon
Korea in the 1860s shortly after the
French campaign against Korea (1866).
Heungseon Daewongun ordered development of bullet-proof armor because of increasing threats from Western armies.
Kim Gi-du and
Gang Yun found that
cotton could protect against bullets if thick enough, and devised bullet-proof vests made of 30 layers of cotton. The vests were used in battle during the
United States expedition to Korea (1871), when the US Navy attacked
Ganghwa Island in 1871. The US Army captured one of the vests and took it to the US, where it was stored at the
Smithsonian Museum until 2007. The vest has since been sent back to Korea and is currently on display to the public. ==Modern period==