The Sacred Island of Okinoshima: A Forbidden Paradise Where 80,000 National Treasures Sleep

Imagine an island so sacred that for over 1,600 years, it has remained virtually untouched by human presence. Located 60 kilometers off the coast of Kyushu in the Genkai Sea, Okinoshima Island stands as one of Japan's most mysterious and spiritually significant sites. In 2017, this "Island of the Gods" along with its associated sites was inscribed as a UNESCO World Heritage Site, recognizing its outstanding universal value as a rare example of ancient maritime worship that continues to this day.

The entire island serves as a shintai (divine body), making it one of the most sacred spaces in Japan. Women have never been allowed to set foot on the island, and even today, male visitors are strictly limited to Shinto priests who maintain the shrine. This extraordinary preservation of ancient taboos has protected not only the island's pristine natural environment but also an archaeological treasure trove of approximately 80,000 artifacts, all designated as National Treasures of Japan.

Why Okinoshima Became a World Heritage Site: The Universal Value of Maritime Faith

The World Heritage designation encompasses eight component sites that together tell the story of how ancient maritime rituals evolved into a living religious tradition. The Outstanding Universal Value lies in two key aspects: first, the site demonstrates important exchanges of values during a crucial period in East Asian history (4th to 9th centuries) when Japan, Korea, and China engaged in active maritime trade and cultural exchange. Second, it represents an exceptional example of the tradition of worshipping a sacred island that has evolved from ancient nature worship into organized Shinto practices.

The ritual sites on Okinoshima provide an almost untouched archaeological record of how religious practices changed over 500 years. The progression from rituals performed on top of huge rocks (iwakura) to those conducted in the shadows of rocks, then to semi-exposed areas, and finally to open-air ceremonies on flat ground, perfectly illustrates the evolution of Japanese indigenous faith from nature worship to formalized Shinto practices.

The "Sea Shosoin": Understanding the 80,000 National Treasures

Often called the "Shosoin of the Sea" in reference to the famous treasure repository in Nara, Okinoshima has yielded one of the most spectacular collections of ritual offerings in East Asia. These artifacts were not buried or hidden but rather placed as offerings during state-sponsored rituals praying for safe sea voyages and successful diplomatic missions.

The treasures include exquisite items that showcase the international nature of ancient maritime trade: pure gold finger rings comparable to those found in Korean royal tombs, bronze mirrors including 21 precious triangular-rimmed mirrors with divine beasts designs, thousands of beads made from materials sourced across Asia, iron ingots from the Korean peninsula (precious in iron-poor ancient Japan), miniature weaving looms representing some of the oldest textile tools in existence, and fragments of cut glass bowls from as far away as Sassanid Persia.

What makes this collection truly remarkable is that every single one of these 80,000 items has been designated as a National Treasure, making the Munakata Taisha Shinpokan (Sacred Treasure Hall) one of the few museums in the world where every exhibited item holds the highest level of cultural designation.

The Three Shrines of Munakata: A Divine Trinity Across the Seas

The Munakata Taisha shrine complex consists of three shrines, each dedicated to one of the three Munakata goddesses born from the mythological union of the sun goddess Amaterasu and the storm god Susanoo. These three goddesses have protected maritime routes for over 1,600 years.

Okitsu-miya on Okinoshima Island enshrines Tagorihime-no-kami, the eldest goddess. The entire island serves as the shrine grounds, with the current shrine buildings dating to the 17th century, nestled protectively among massive sacred rocks. Access remains strictly forbidden except for one shrine priest who lives alone on the island in 10-day rotations, maintaining daily rituals.

Nakatsu-miya on Oshima Island (11km from mainland Kyushu) enshrines Tagitsuhime-no-kami, the second goddess. This shrine is accessible to visitors via a 15-25 minute ferry ride from Konominato Port. The island also features the Okitsu-miya Yohaisho, a worship hall from which people can pray toward the forbidden Okinoshima Island, visible on clear days 49km across the sea.

Hetsu-miya on mainland Kyushu in Munakata City enshrines Ichikishimahime-no-kami, the youngest goddess. As the most accessible of the three shrines, it serves as the center of Munakata worship, featuring magnificent architecture including buildings relocated from Ise Grand Shrine, and the Shinpokan museum housing the Okinoshima treasures.

Sacred Rituals and Living Traditions: The Miare Festival

The faith that began with ancient state rituals continues vibrantly today through various ceremonies and festivals. The most spectacular is the Miare Festival, held annually on October 1st as part of the Autumn Grand Festival. This maritime procession sees over 150 fishing boats escort two sacred vessels carrying the spiritual essences of the goddesses from Oshima Island to the mainland.

The boats, decorated with colorful flags and banners, create a magnificent parade across the Genkai Sea, demonstrating how the local fishing communities continue to honor the goddesses who protect their livelihoods. The festival culminates with the three goddess spirits reuniting at Hetsu-miya for the three-day autumn celebration, featuring traditional performances including horseback archery (yabusame) and ancient court dances.

Throughout the year, the strict taboos that have protected Okinoshima for centuries remain in force: nothing may be removed from the island, not even a blade of grass or a pebble; anyone who lands on the island must perform misogi (ritual purification) by bathing naked in the sea; and nothing seen or heard on the island may be spoken of elsewhere, earning it the name "Oiwazu-sama" (the island of which we do not speak).

The Shinbaru-Nuyama Tumuli: Tombs of the Sea Lords

The Shinbaru-Nuyama tumulus group in Fukutsu City provides crucial evidence of the powerful Munakata clan who conducted the Okinoshima rituals and controlled these vital sea routes. Built between the 5th and 6th centuries on a plateau overlooking the sea route to Okinoshima, the group consists of 41 tombs including five keyhole-shaped tumuli (kofun), 35 round tumuli, and one rare square tumulus.

Archaeological excavations have revealed artifacts that directly connect these tombs to the Okinoshima rituals, including iron axes identical to those offered on the sacred island and mirrors of the same type found among the island treasures. The tombs' positioning, with clear views toward Okinoshima and the Korean peninsula beyond, emphasizes the Munakata clan's role as maritime intermediaries between the Yamato court and continental Asia.

Today, these ancient tombs dot the rural landscape among rice paddies, offering visitors a glimpse into the power and prestige of the clan that maintained Japan's most important maritime shrine for centuries.

Visiting the Sacred Sites: A Practical Guide for International Visitors

While Okinoshima Island itself remains forbidden to visitors, the other components of this World Heritage site offer rich experiences for those seeking to understand Japan's maritime spiritual heritage.

Munakata Taisha Hetsu-miya: The most accessible site, located in Munakata City. From JR Togo Station (on the Kagoshima Main Line between Hakata and Kokura), take a bus to Munakata Taisha-mae stop (15 minutes). The shrine grounds are extensive, including the Shinpokan museum (admission: 800 yen for adults), which houses rotating displays of Okinoshima treasures. The Takamiya sacred ground within the complex is considered one of Japan's most powerful spiritual sites.

Oshima Island: Take a bus from JR Togo Station to Konominato Port (20 minutes), then board the ferry to Oshima (15-25 minutes, 570 yen one way). Ferries run 5-7 times daily. On the island, Nakatsu-miya shrine is a 5-minute walk from the port. The Okitsu-miya Yohaisho worship hall requires a 30-minute hike but offers the closest permitted view of sacred Okinoshima. The island can be explored on foot or by rental bicycle.

Shinbaru-Nuyama Tumuli: From JR Fukuma Station, the site is 15 minutes by taxi or 25 minutes by bus to Nuyamguchi stop plus a 15-minute walk. A viewing platform provides panoramic views of the tomb group with the sea and Oshima Island as backdrop. Admission is free, and the rural setting offers peaceful walks among the ancient tombs.

Cultural Insights: Understanding the Significance for Modern Japan

The Sacred Island of Okinoshima represents far more than an archaeological site or religious shrine—it embodies Japan's relationship with the sea and the continuity of spiritual practices across millennia. In an age when many religious sites have been transformed by tourism, Okinoshima stands as a remarkable example of how traditional taboos and community respect can preserve both tangible and intangible heritage.

For the local fishing communities, the Munakata goddesses remain active protectors of their livelihoods. Fishermen still pray at the shrines before heading out to sea, and the annual Miare Festival reinforces communal bonds while honoring ancient traditions. The site demonstrates how indigenous beliefs evolved into organized religion while maintaining their essential character—a process that shaped Japanese culture profoundly.

The international significance of the Okinoshima treasures reveals Japan's historical position as the eastern terminus of the Silk Road's maritime routes. The offerings from Korea, China, and even Persia demonstrate that Japan was never isolated but rather selectively engaged with the outside world, adopting and adapting foreign influences while maintaining its own cultural identity.