The name 'Genbudo' is derived from the Genbu, a mythological black tortoise associated with the north, due to the dark color of the basalt.
The site provided the inspiration for the term 'Genbudo' in geology, which was first coined by Dr. Shigeo Harada in 1884 to describe this type of columnar jointing.
The basalt columns are composed of lava that flowed from a volcano and cracked as it cooled and contracted, creating regular geometric shapes.
During the Edo period, workers extracted stones from the caves using iron chisels, leaving behind the vertical patterns visible today.
The five caves are named after the four mythological Chinese directional guardians, plus an additional central cave, to represent the compass directions.
Genbudo Park is a geological site in Toyooka featuring five caves formed from natural basaltic columns. The basalt pillars were created approximately 1.6 million years ago during volcanic activity and subsequent rapid cooling. The site served as a quarry during the Edo period, providing stone for construction projects in the region. The main cave, Genbudo, was designated a National Natural Monument in 1931. The park is situated along the banks of the Maruyama River. The basalt columns exhibit a distinct hexagonal cross-section, known as columnar jointing. Visitors can walk through a path that connects the five distinct caves: Genbudo, Seiryudo, Byakkodo, Nanjudu, and Kockodo. The site is a core component of the San'in Kaigan UNESCO Global Geopark.
The entrance to the main Genbudo cave, where the geometric precision of the hexagonal columns is most visible against the rock wall.
Wear comfortable walking shoes with good grip as the paths can be uneven near the rock faces.
Bring a flashlight if visiting late in the afternoon, as the interiors of the deeper caves can be dim.
Check the park's official website for any trail closures due to recent rainfall or rockfall safety maintenance.
Do not attempt to enter the caves beyond the marked safety barriers, as rock instability is a monitored risk.
Stay strictly on designated walking paths; do not climb on or touch the basalt pillars to prevent erosion and personal injury.
