Abastion, called chi in Korean, was a structure projecting outward from a fortress wall, which was designed to attack approaching enemies from the side. The name chi comes from the Chinese character for pheasant, because pheasants are good at hiding and peeping. Hwaseong Fortress has a total of 10 bastions.
The Western Bastion I is located where the fortress wall is sharply bent between the Northwestern Corner Pavilion and the Western Artillery Pavilion. As this was an important defense point, the bastion was built very close to the corner pavilion.