Jang Yeong-sil

Jang Yeong-sil (Korean: 장영실; Hanja: 蔣英實; 1390 - after 1442) was a Joseon Dynasty mechanical engineer, scientist, and inventor (1392-1897). Despite the fact that Jang was born a peasant, King Sejong allowed him to work at the royal palace. Jang's inventions, such as the Cheugugi (the rain gauge) and the water gauge, highlight the Joseon Dynasty's technological advancements.

Jang's fame earned him admission to the royal court at Hanseong (modern-day Seoul), where selected commoners performed for the king and his advisers. Jang exceeded Sejong's expectations in crafts and engineering, earning Jang a position as a government official in the palace. The gifted scientists hired through Sejong's new program worked at the Hall of Worthies.

Jang's extraordinary achievements earned him Sejong's trust. Some government officials were envious of Jang, especially since he had accomplished so much despite his common ancestry. Furthermore, Korean Confucianism, which was deeply rooted in Joseon society, held scientists and engineers in low regard, similar to craftsmen.

In 1442, Sejong commissioned Jang Yeong-sil to create a gama, a lavishly decorated Korean sedan chair. Jang was held responsible for the gama breaking while Sejong was traveling. Despite Sejong's opposition to the decree, Jang was imprisoned for an extended period of time and expelled from the royal palace. Later events in Jang's life, including his death date, were not documented. It is unlikely, but Jang Yeong-sil died during the reign of Joseon's 7th king, Sejo of Joseon (r. 1455-1468).

Birthdate: 1390
Birthplace: South Korea
Died: after 1442