Civilizations all produce men and women of great intellect. Leonardo da Vinci, Isaac Newton, and Ada Lovelace are among the greatest geniuses that the West has produced over the past six hundred years. Six hundred years ago, on the Korean peninsula, there lived a genius who ought to be spoken of alongside the likes of the three listed above: Jang Yeong-sil. Like Leonardo da Vinci, Jang Yeong-sil was of humble origins. He was born a peasant and broke class barriers due, in part, to his intellect. He invented a rain gauge, sundial, water clock, and celestial globe. Recently, Jang Yeong-sil has been portrayed in various movies and period dramas.
Jang Yeong-sil was born a peasant but lived during the reign of the open-minded King Sejong the Great (r.1418–1450). King Sejong wanted to select government officials based on talent rather than heredity. Recognized locally for his talents, Jang Yeong-sil was given the opportunity to travel to Hanseong (Seoul) and prove himself before the king. Deeply impressed, King Sejong allowed him to work at court. It should be noted that Jang Yeong-sil among selected commoners to appear before the king to prove their abilities. Below is a brief look at several of Jang Yeong-sil’s most important inventions.
Cheugugi (Rain Gauge) 1441 -measured precicipation, developed in response to the people’s need to better manage water and mitigate the deleterious effects of drought as much as possible.
Angbu Ilgu (Sundial) — tells times accounting for the seasons and included animal shapes so as to be of some use to illiterate people
In addition to these inventions, King Sejong had Jang Yeong-sil study weaponry so as to make necessary improvements. Though highly respected by King Sejong for his knowledge of metals and engineering, Jang Yeong-sil faced considerable resentment among the nobility because he was of such humble origin. Many of the elites of the time had little to no respect for social mobility. The last records of Jang Yeong-sil come from 1442 and no date of death is recorded.
Jang Yeong-sil ranks as one of the greatest geniuses in Korean history. He developed his rain gauge over two centuries before the Europeans had the concept. His water clock (influenced by Arabic and Chinese precursors) was developed in response to the need to tell time in the absence of the sun.