Heumgyeonggak Pavilion was in the east of the Gyeonghaeru Pavilion. King Sejong bestowed upon it its namesake, which translates to "respect heaven and know the times and seasons." It was built to store astronomical tools, including the world’s best automatic water clock, until the 15th century.

Heumgyeonggak Pavilion was built in 1438 during King Sejong’s reign. It was destroyed by fire in 1553, during the eighth year of the reign of King Myeongjong. Only after more than 400 years was it restored in 1995, along with Hamwonjeon Hall, Gangnyeongjeon Hall, and Sajeongjeon Hall.

In ancient East Asian countries, it was necessary to figure out climate change. As it was a primarily agrarian society, one of most important duties of the king was to figure out the time of climate change and the good time of growing crops. This had a direct impact on people’s quality of life. Therefore, King Sejong asked Jang Yeongsil, who was a talented servant, to invent the sundial and waterclock.

Both the sundial and waterclock were very useful for farming. The sundial helped to tell the time of day and even the division of seasons. On the other hand, Okru, the water clock, even provided more accurate information. It is an automatically operating astronomical clock that rings every hour and shows the sun’s movement over time. It can tell the 24 solar terms regardless of the weather and sunlight. However, as it needs to maintain a certain amount of water, it could not be placed outside on snowy and rainy days. That’s why the Heumgyeonggak Pavilion needed to be built.