Kaga Kugedo is a spectacular coastal landmark located at Kugedobana on the northern coast of Matsue, in the former Shimane Town area. Facing the Sea of Japan, this dramatic site combines enormous sea caves carved by the power of the ocean with ancient Japanese mythology and local religious traditions.
The name “Kaga” comes from the name of the nearby settlement, while “Kugedo” simply means a cave. In 1927, the site was designated by the Japanese government as a Place of Scenic Beauty and Natural Monument under the name “Kugedo.” It is also part of Daisen-Oki National Park.
With its towering cliffs, sea caves, legends, and powerful waves, Kaga Kugedo is a remarkable destination where nature, geology, mythology, and faith come together.
The name “Kugedo” refers to a cave, and the caves here were formed through a long process of geological activity and coastal erosion. The underlying rocks, including andesite and tuff, developed faults and cracks through movements of the Earth’s crust.
Over countless years, strong waves and winds from the Sea of Japan attacked these weakened sections of rock. Gradually, the cracks widened and developed into the enormous sea caves and rock formations visible today.
Kaga Kugedo consists of two principal caves: Shin-Kugedo, or the New Cave, closer to the sea, and Kyu-Kugedo, or the Old Cave, farther inland. Although they were formed in the same coastal environment, they have very different natural and cultural characteristics.
The rocks around Kaga Kugedo date back more than 10 million years and include andesite and basaltic lava as well as volcanic debris produced by ancient volcanic activity.
Around Shin-Kugedo, visitors can observe features such as pumice tuff and graded bedding, while the area around Kyu-Kugedo contains andesite lava and volcanic breccia. These formations provide valuable clues about the geological history of the Shimane Peninsula.
The area is recognized as an important geological site within the Shimane Peninsula Geoheritage area and is of interest not only to travelers but also to researchers and those interested in the geological formation of the Japanese archipelago.
Shin-Kugedo, also known as Kamigakuredo, is an impressive sea cave extending for approximately 200 meters. It has a tunnel-like structure in which three entrances are connected internally.
When sea conditions are calm, sightseeing boats can enter the cave, allowing visitors to experience its vast interior from the water. Light filtering in from the entrances, the sound of waves, and the surrounding rock walls create an otherworldly atmosphere.
Shin-Kugedo is also deeply connected with the mythology recorded in the Izumo no Kuni Fudoki, an ancient geographical record compiled in the Nara period. According to the tradition, this cave is the birthplace of Sada-no-Ōkami, an important deity in the mythology of the Izumo region.
The legend tells that when the deity was about to be born, his mother, Kisakahi-hime-no-Mikoto, prayed that if her child was truly the son of the deity Masura, a golden bow and arrow would appear.
A golden bow and arrow then came floating toward her. When the mother looked into the dark cave and exclaimed at how dark it was, she used the golden arrow to pierce through the rock. The opening allowed light to enter the cave.
According to the tradition, the word “kaka,” meaning something associated with brightness or light in the local story, became connected with the place name Kaga. This ancient legend gives the landscape a cultural dimension that goes far beyond its geological appearance.
The original shrine site of Kaga Shrine was once located inside the cave area, and a small shrine remains to indicate the former sacred site. Even today, Shin-Kugedo retains an atmosphere of being a place associated with the divine.
Located farther inland, Kyu-Kugedo is also known as Hotoke-Kugedo. Although its entrance is only about 5.5 meters wide, the cave opens into a surprisingly large interior approximately 50 meters deep and more than 10 meters high.
The cave is associated with the folk belief of Sai-no-Kawara, a symbolic place described in Japanese Buddhist tradition as a riverbank where children who died young are believed to stack stones.
For generations, visitors have placed stones inside the cave and left offerings such as toys and clothing associated with children who passed away. The accumulated stones and offerings have created a solemn atmosphere within the cave.
The tradition reflects an enduring Japanese expression of grief and remembrance. For overseas visitors, it is important to understand that the site is not simply a geological cave but also a place where local folk beliefs and memories have been preserved.
Walking paths and tunnels have been developed around the area, allowing visitors to explore Kyu-Kugedo safely from land.
From March through November, sightseeing boats operate in the Kaga Kugedo area, offering a journey of approximately 50 minutes along the rugged coastline.
The boats travel into Shin-Kugedo when sea conditions permit, bringing visitors directly into the dramatic landscape associated with the ancient myths. The experience is especially memorable when sunlight enters the cave and illuminates the dark rock walls.
The boats depart from Marine Plaza Shimane, which also has a visitor center where travelers can learn about the area’s geology, mythology, and local history before or after their cruise.
Offshore from the eastern entrance of the cave is Matoshima Island, which features its own distinctive rock arch. Seen from the sea, the island and surrounding cliffs form part of an impressive coastal panorama.
The boat journey provides a perspective that cannot be experienced from land, revealing the scale of the cliffs and caves along the rugged coastline.
Kaga Shrine is dedicated to Kisakahi-hime-no-Mikoto, the mother deity associated with the legend of Shin-Kugedo.
The Izumo no Kuni Fudoki describes how the mother deity used a golden arrow to pierce the dark rock chamber, allowing light to enter. This story is closely associated with the origin of the name Kaga and has remained an important part of the area’s religious tradition.
Another deity, Sarutahiko-no-Mikoto, later came to be enshrined alongside her. Kaga Shrine continues to serve as an important center of local worship.
Kaga Kugedo is far more than a sea cave created by erosion. Its cliffs and caves demonstrate the tremendous power of the Sea of Japan, while its ancient rocks preserve evidence of the geological history of the Shimane Peninsula.
At the same time, the caves are closely associated with some of the oldest written traditions of the Izumo region. The story of the birth of Sada-no-Ōkami, the golden arrow, and the sacred origin of Kaga connects the physical landscape with the mythology of ancient Japan.
Kyu-Kugedo adds another cultural layer through the Sai-no-Kawara tradition and the generations of people who have visited the cave to remember those who died young.
From the cliffs of Kugedobana, visitors can look across the vast Sea of Japan and appreciate the rugged coastline shaped by waves and wind. Inside the caves, the atmosphere changes completely: daylight becomes dim, the sound of waves echoes against the rock, and the immense walls create a sense of isolation and mystery.
A sightseeing cruise offers the most dramatic way to appreciate this landscape, especially when the boat enters Shin-Kugedo. The combination of darkness inside the cave, sunlight from the entrances, and the blue sea outside creates an unforgettable visual experience.
Izumo is famous for its ancient mythology, and Kaga Kugedo offers a different way to encounter that cultural heritage. Rather than being preserved only in books or museums, the mythology here remains connected to an actual landscape of cliffs, caves, sea, and shrines.
The stories associated with the caves help explain how ancient people understood and interpreted dramatic natural features. The boundary between nature and the sacred is particularly strong here, making Kaga Kugedo an intriguing destination for travelers interested in Japanese mythology and traditional beliefs.
Kaga Kugedo brings together three extraordinary elements: spectacular coastal geology, ancient Japanese mythology, and centuries of local religious tradition.
The immense sea caves were carved by the power of the ocean over geological time, while legends recorded in the Izumo no Kuni Fudoki have given the landscape a spiritual meaning passed down through generations.
For travelers exploring the Shimane Peninsula, a visit to Kaga Kugedo offers the opportunity to experience both the physical power of nature and the stories that people have attached to it. Whether viewed from a sightseeing boat, explored along the walking paths, or simply admired from the coastline, this remarkable place reveals a mysterious and deeply atmospheric side of the Izumo region.