Heumgyeonggak Pavilion (Hanja: 欽敬閣) in Gyeongbok Palace lets us glimpse how the king of an agrarian society strived to understand the movements of celestial bodies and to accurately measure time for the benefit of his subjects. In 1438, King Sejong the Great ordered the construction of Heumgyeonggak, where many of his scientific inventions, including the rain gauge, sundial and water clock, as well as instruments for astronomical observation, were installed.
Inside the Pavilion, there is a sundial and water clock invented by Jang Yeong-sil, an inventor during the reign of King Sejong the Great. Jang Yeong-sil, the inventor of the sundial in 1434, was a scientific genius. His sundial not only tells the time of day, it also indicates 24 subdivisions of the season. The fact that this sundial was built in the shape of a hemisphere shows that Joseon scientists at the time could accurately read the sun’s movement and knew that the Earth is round. Jang and his assistants also developed clepsydras (water clocks), in which figurines propelled by water automatically strike a wooden gong, drum, and bell to tell the time.
Hamwonjeon Hall (Hanja: 含元殿) is a building used for Buddhist events, is also believed to have been built during Sejong’s reign. After their destruction by fire several times, these buildings were last rebuilt in 1888, only to be dismantled in 1917 (seven years after Korean Empire annexation by Japan), ostensibly to provide building material for Changdeok Palace, which had been destroyed by fire that year. As with Heumgyeonggak Pavilion, Hamwonjeon Hall was restored in 1995.