Gyeongbokgung Palace was built with fence walls surrounding it, and four gates were placed in all directions. The watchtowers were then built at both ends of the fence wall connecting Gwanghwamun Gate. They are the Dongsipjagak and Seosipjagak, which were placed in the east and west, respectively.

The watchtowers have gone through several hardships since the beginning of the Japanese invasion. The Seosipjagak was demolished in 1923 to make way for a tram line, while the Dongsipjagak had to be removed from the Gyeongbokgung Palace along with the relocation of Gwanghwamun Gate due to the Japanese Government General of Korea's office building construction. Dongsipjagak is now standing lonely in the middle of the road due to the extension and construction of roads on both sides.

Dongsipjagak is a high watchtower with no doors to enter. In the past, there were stairs for the guards to climb up and down from the top of the tower to stand on guard. The roof helps to block the rain, and its wall, called "Yeojang”, protects the guards from arrows and bullets. It used to be an excellent combat facility, and some traces of bullet holes are still left on the wall of Dongsipjagak, showing the hard days in the past.

Seosu is an imaginary animal believed to drive out evil acts. It used to be placed on the staircase of the Dongsipjagak. For a period of time, people thought it was lost and left somewhere during the Japanese invasion. Fortunately, it was verified that the Seosu of Dongsipjagak was at Changdeogung Palace in 2019. The Seosu used to guard the Seosipjagak looked similar to each other. As the two watchtowers were constructed in a symmetrical structure, it is presumed that the Seosu was also made in pairs. Also, there was a photo taken with the two watchtowers, proving that it was from Dongsipjagak.