The archaeology of World War II karst defences in the Pacific

During World War II, the Japanese military, using either their own or civilian labour, excavated tunnels into the limestone of many Pacific islands and modified natural caves for use as command posts, hospitals, combat positions, storage, and shelter. Civilians also used caves to shelter themselves during the war. This article introduces the archaeology of WWII caves and tunnels referred to collectively as ‘karst defences.’ While karst defences exist across the Pacific, little is known about these sites both historically and archaeologically. Based on a study in Saipan, Commonwealth of the Northern Mariana Islands, and analysis of karst defence construction and function, this article demonstrates that karst defence use extends beyond what has been described in historical accounts. The authors find that the sites in Saipan were used by three different groups of people and identifies distinct Japanese military and civilian sites and evidence of post-war use by the United States.