Bukdong Jeokdae, Bukdongchi

The Bukdong Jeokdae was a defensive structure built to the sides of the fortress gates in order to block the enemies. The inner wall was equipped with ports to attack enemies in case of emergency.
Crenels are holes in a rampart or fortress through which bullets would be shot secretly at enemies.

While Porus and Chiseong completely protruded from fortress walls, this Jeokdae has half of it inside the walls.

The Bukdongchi was a Chiseong connected to the Bukdong Jeokdae. It had a Seonggakwi, a low wall that permitted soldiers to hide themselves from the enemy. The Seonggakwi had three openings which one could view outside through them.