A bastion, 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 Eastern Bastion III, located between the Eastern Guard Pavilion II and the Southeastern Corner Pavilion, has the widest width and the shortest protrusion length among the bastions of Hwaseong Fortress. This design is because the bastion was built atop a steep slope. The bastion and the adjacent walls have maintained their original structure.