Genbudo, located in Toyooka City, is a beautiful cave complex designated as a national natural monument, located on the banks of the Maruyama River. The area is known for the magnificent hexagonal and square columnar joints formed during the cooling and solidification process of magma that flowed out from volcanic activity that occurred 1.6 million years ago. The name Genbudo is derived from Genbu, one of the four gods, or the divine beast that presides over the north, and the cave's north-facing position is believed to be the origin of its name. One of the highlights of Genbudo Cave is its large, regular columnar joints. This geological phenomenon is related to cooling rates and rock properties, providing a spectacle that can be considered a work of art created by the forces of nature. The cave complex includes not only Xuanwu Cave, but also other caves named after the other four gods, such as Blue Dragon Cave, White Tiger Cave, and Suzaku Cave, each with its own unique shape and charm. Genbu-dong has long been a favorite of the local people and has been the subject of research because of its geological value. In addition, part of Genbudo Cave collapsed during the Kitatajima Earthquake of 1925, but it is deeply connected to the history of the area, as some of the collapsed rocks were later used to build a sea wall in the nearby Kinosaki hot spring resort area.