Approximately 440 cave fortifications that were developed in Jeju during the Japanese colonial period have been discovered.

The Korea Cave Safety Research Institute and the Jeju Island Cave Research Journal announced that 448 Japanese cave camps built in the province were confirmed in 120 areas as a result of conducting site investigations based on testimonies and documentaries.

The researchers explained that additional excavations and academic research are needed, saying that various types of fortifications have been built depending on the location and tactical use.