The face of a beast is depicted on this convex roof-end tile, with its protruding eyes, nose, mouth, and teeth emphasized. The beast face motif was used to ward off evil spirits.
There are two types of beast faces that are featured on such roof-end tiles: those with rectangle-shaped mouths and those with flipped-trapezoid-shaped mouths. The former is only found in Ji’an, China, where Gungnaeseong was located. The latter, on the other hand, is only found in the Pyongyang region.