Kochijima Island is a small island in the middle reaches of the Kozagawa River in Kozagawa Town, Higashimuro District, Wakayama Prefecture. For generations, the island has been deeply revered by people living along the Kozagawa River.
Locally, the island is affectionately known as “Kōttama” or “Kōottama,” and the island itself is regarded as a sacred object of worship.
About three kilometers upstream from the mouth of the Kozagawa River, a small island can be seen quietly resting in the gentle current. Unlike an ordinary Japanese shrine, Kochijima has no shrine building or torii gate. This is one of its most distinctive characteristics.
Instead of placing the divine presence inside a man-made structure, the island itself is regarded as sacred. It preserves a form of ancient Japanese nature worship in which natural features such as rocks, mountains, rivers, and islands can be considered dwelling places of the divine.
Formed from igneous rock, Kochijima stands out against the surrounding landscape of clear water and forest-covered mountains. The peaceful river flowing around the island creates an atmosphere of remarkable stillness, as if time has stopped.
A sacred stone is said to stand at the center of Kochijima, and local people have traditionally believed that a divine presence resides on the island.
During religious ceremonies, only designated representatives are permitted to land on the island. They offer seawater and sacred sake before praying at the sacred site.
The deity enshrined at Kawachi Shrine is said to be Susanoo-no-Mikoto, a powerful deity in Japanese mythology. In the local community, however, the deity is widely revered as Kawachi Daimyōjin.
Kawachi Daimyōjin has traditionally attracted the faith of both people connected with the mountains and those connected with the sea. In this sense, the deity represents the spiritual culture of the entire Kozagawa River basin, where mountain communities and maritime communities have long been connected by the river.
Even the stones on the riverbank where ceremonies are held are believed to possess spiritual power. There is also a local story that soldiers leaving for war once carried stones from around Kochijima as protective charms.
For local people, Kochijima is therefore far more than a scenic attraction. It is a place deeply connected with daily life, prayer, community identity, and traditional beliefs.
Every year, Kochijima becomes the focus of one of the most important traditional events in the Kozagawa area: the Kōchi Festival, also known as the Mifune Festival.
The festival has a long history and has been designated an Important Intangible Folk Cultural Property of Japan.
One tradition connects the festival with the Kumano Navy, a powerful maritime force associated with the Kumano region during the Genpei War. The festival is said to preserve memories of prayers for victory and triumphant returns from battle.
The festival was already highly regarded by the early 19th century. The Kii Zoku Fudoki, a historical geographical record compiled in 1839, described it as one of the most remarkable festivals in the region between Hikiura and Shingu.
The festival normally begins with an eve celebration on the fourth Saturday of July, followed by the main festival on Sunday.
Five communities along the Kozagawa River—Koza, Furuta, Takaike, Utsugi, and Tsukinose—take responsibility for different parts of the event, each preserving its own traditions and role.
The highlight of the Kōchi Festival is undoubtedly the spectacular procession of Mifune boats traveling upstream along the Kozagawa River.
The Koza area once prospered through whaling, and the boats used in the festival are beautifully decorated. Their elaborate appearance evokes the atmosphere of a traditional Japanese court procession or historical picture scroll.
Three brilliantly decorated Mifune boats form the center of the procession, accompanied by yakatabune pleasure boats, oar boats, and boats carrying lion dancers.
Slowly making their way toward Kochijima, the decorated boats create an unforgettable scene. The sound of conch shells and traditional boat songs carries across the river, making the festival feel like a living scene from Japan’s past.
As evening approaches, the Mifune boats circle Kochijima three times in a clockwise direction.
As darkness falls, lights from the boats are reflected on the surface of the river. The illuminated vessels, quiet current, and traditional songs combine to create an almost dreamlike atmosphere.
For visitors, this evening ceremony is one of the most memorable moments of the festival, offering a rare opportunity to witness a traditional river ritual in a setting that has changed little in character over the centuries.
The Kōchi Festival also features the Kozaryu Shishimai, or Koza-style lion dance, which is regarded as one of the important traditions associated with the development of lion dancing in the Kumano region.
This style, known as the Koza School, belongs to the broader tradition of Kumano lion dances associated with Ise Dai Kagura, a form of ritual performance historically connected with the Ise Grand Shrine tradition.
Performances include several different dances, such as the “Dance of the Sacred Wand,” “Wild Lion Dance,” and “Sword Dance.”
The energetic movements of the dancers, combined with the sounds of flutes and drums echoing across the riverbank, create a powerful and exciting atmosphere. The performance demonstrates how religious rituals and traditional performing arts have been passed down together through generations.
Near the end of the festival, young men known as Sengō take part in a dramatic oar-boat race.
The competitors power their boats forward with great force, rapidly rowing along the river while spectators cheer from the riverbanks. The race adds a lively and competitive element to the otherwise solemn religious ceremonies.
A fireworks display is also held during the festival, illuminating the night sky above the Kozagawa River.
The reflection of fireworks on the water, combined with the lights of the Mifune boats, creates a spectacular nighttime scene unique to the Kōchi Festival.
The Kōchi Festival is associated not only with stories of the Genpei War but also with older local folklore.
According to one legend, Kawachi-sama is a snake deity who was in love with a tai sea bream living around Kuryujima Island downstream.
It is said that once a year, the tai fish traveled to visit Kawachi-sama aboard a Mifune boat. This romantic and mysterious story is said to have become one of the origins of the festival.
The tale reflects the imaginative character of local folklore and the close relationship between nature, animals, rivers, and spiritual belief in the Kozagawa region.
Another distinctive tradition of the Kōchi Festival is the role of the Shōrō.
Two boys and one girl are selected from elementary school children in the Koza area to serve in this special role. During the festival, they are treated as beings who serve the deity.
In the past, the children stayed overnight at the shrine and were forbidden even to walk directly on the ground in order to avoid ritual impurity.
Although the tradition has been simplified in modern times, the Shōrō remain an important symbol of the sacred nature of the festival.
For centuries, people have enjoyed watching the Kōchi Festival from yakatabune, traditional roofed pleasure boats.
Before modern roads and transportation, boats were an important means of travel along the Kozagawa River. During the festival, relatives and friends would gather aboard these boats to enjoy the festivities together, making the event one of the highlights of summer.
Although fewer boats are used today, watching the Mifune procession and lion dances from the water remains a particularly beautiful experience.
Feeling the river breeze while watching the decorated boats glide past offers a unique perspective on the festival and provides a memorable way to experience the traditional culture of the Kozagawa River.
One of the traditional foods associated with the Kōchi Festival is Kashiwazushi.
This dish consists of rice prepared in the style of mixed sushi and wrapped in the leaves of the akamegashiwa tree. The leaves give the dish a distinctive fragrance and were traditionally valued for their natural preservative properties.
Other local dishes served during the festival include freshwater shrimp, grilled flying fish, broad beans, and namasu, a traditional dish of finely sliced vegetables or fish dressed with vinegar.
Food is an important part of the festival experience, providing visitors with another way to discover the culinary traditions of the Kozagawa region.
Kochijima Island and the Kōchi Festival preserve an important part of the spiritual and cultural heritage of the Kozagawa River basin.
The festival has been supported by both mountain communities and people whose lives are connected with the sea. Its rituals demonstrate how the river has historically connected different communities and how nature has remained at the center of local beliefs.
The magnificent Mifune procession, powerful lion dances, traditional boat songs, sacred ceremonies, and illuminated boats all come together to create a festival unlike any other.
At the heart of it all is Kochijima itself, a small sacred island without a shrine building or torii, where nature itself is regarded as divine.
For travelers exploring the Kii Peninsula, Kochijima and the Kōchi Festival offer a rare opportunity to experience a living tradition in which river, mountain, community, mythology, and faith remain closely intertwined.
If you visit Kozagawa, taking time to learn about Kochijima and the Kōchi Festival will provide a deeper understanding of the spiritual traditions and local culture that have shaped this beautiful river valley for generations.