Abstract
The purpose of this study is to analyze the octagonal buildings in the era of three kingdom and the unified Silla. There are 10 octagonal building remains of 20 polygon builing remains. The octagonal buildings are very important as the unique buildings style of Goguryeo. And the octagonal shape symbolized as eight signs of divination(八卦) of ancient religion and one of Buddhist doctrine in Korea and China. So the octagonal buildings had used as ritual building or Buddhist pagoda from 3rd Century of Goguryeo to the unified Silla. The octagonal Buddhist pagodas can find the origin from the twin remains of Goguryeo palace in Hwandosansung(丸都山城). The 4 of Goguryeo octagonal Buddhist pagodas had similar shape but the Yeongmyosa(靈廟寺) twin pagodas in the unified Silla was smaller than Goguryeo octagonal Buddhist pagodas. The other five buildings assume as multi-storied building. They did not have the foundation while The octagonal Buddhist pagodas had foundation. The first floor columns plan of buildings was difficult to use the space so upper floor might have used special purpose.