A breathtaking new analysis of an ancient iron spear unearthed on Okinoshima - Japan's revered "Island of the Gods"- has revealed East Asia's earliest known example of a gold-inlaid weapon. This exquisitely crafted artifact, first discovered in 1954 beneath a sacred boulder near the Okitsu-gū Shinto shrine, is now shedding extraordinary light on the spiritual sophistication and metallurgical expertise of Japan's early Yamato state.
The artifact with sketch of the patterns inlayed on the spear. (Preservation and Utilization Council of “Sacred Island of Okinoshima and Associated Sites in the Munakata Region”)
Unveiling a Sacred Masterpiece
Measuring just over 30 centimeters (12 inches) in length, the iron spear had remained sealed in a gilt bronze sheath and largely unstudied until recently. Now, thanks to advanced X-ray and CT imaging technologies applied by Japan's Cultural Affairs Agency, researchers have uncovered a dense network of inlaid motifs hidden for centuries beneath layers of corrosion. The patterns, which include stylized phoenixes, vine-like arabesques, tortoise-shell designs, and feather or flower elements-were most likely created using kinzōgan, a rare and delicate technique in which gold is embedded into finely carved grooves.
"This spear demonstrates the Yamato state's extraordinary dedication to the spiritual rites held on Okinoshima," said Toshinori Mizuno, head of materials at the Archaeological Institute of Kashihara, reports Arkeonews. "Its complexity reflects both technical mastery and religious reverence".
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3-D image of the spear through the X-ray of a CT scan. (Preservation and Utilization Council of “Sacred Island of Okinoshima and Associated Sites in the Munakata Region”)
A Spear Made Not for War, But for the Divine
Experts believe the spear dates to the late 6th to early 7th century AD, toward the end of the Kofun period, notes a press release from Okinoshima Heritage. Despite its formidable form, the spear was never intended for battle. Instead, it served as a hōnōhin - a sacred offering to the sea deities worshipped at Okinoshima.
The elaborate ornamentation and delicate craftsmanship indicate that this was a votive object of immense spiritual and symbolic significance, possibly produced under direct commission from the Yamato court.
Tadashi Nishitani, professor emeritus of archaeology at Kyushu University, emphasized its importance:
"This discovery is without precedent in Japan. It confirms the scale and sophistication of state-level ritualism during the Kofun period, centered on Okinoshima's sanctity" quotes Arkeonews.
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Island of the Gods: Okinoshima's Eternal Sanctity
Okinoshima Island, situated in the Genkai Sea off the coast of Fukuoka Prefecture, has been a center of sacred maritime rituals since at least the 4th century AD. Administered by the Munakata Taisha shrine, the island played a central role in early imperial ceremonies meant to ensure the safety of sea voyages and diplomatic missions, particularly with the Korean Peninsula.
Today, the entire island is still revered as a kami (divine being) in Shinto belief. Entry is strictly regulated: women are entirely forbidden from setting foot on the island, while male visitors must undergo purification rituals. These centuries-old customs underscore the island's role as a spiritual nexus where religious, political, and natural worlds converge.
More than 80,000 ritual objects, including bronze mirrors, swords, beads, and the gold-inlaid spear, have been excavated from Okinoshima, all of which are designated National Treasures of Japan reports Archeaology Mag.
X-ray transmission photograph of the spearhead within its bronze sheath. (Gangoji Institute for Research of Cultural Property / Preservation and Utilization Council of “Sacred Island of Okinoshima and Associated Sites in the Munakata Region”)
Preserving Japan's Ritual Heritage
The spear's rediscovery is part of a broader initiative by the Cultural Affairs Agency to digitally scan and conserve over 4,200 metal artifacts from Okinoshima. This effort is led by the Preservation and Utilization Council of "Sacred Island of Okinoshima and Associated Sites in the Munakata Region," a collaborative body involving shrine authorities, local governments, and cultural researchers.
Recognized by UNESCO as a World Heritage Site in 2017, Okinoshima remains one of Japan's most spiritually significant and archaeologically rich locations - a place where the divine legacy of the Yamato polity is preserved in both myth and material.
As researchers continue to analyze the spear and other treasures from the island, each artifact brings us closer to understanding the early Japanese worldview: a civilization that fused artistry, power, and devotion on an island where gods walked among men.
Top image: Gilt bronze spear sheath containing iron spear. Source: Preservation and Utilization Council of “Sacred Island of Okinoshima and Associated Sites in the Munakata Region”/Okinoshima Heritage
By Gary Manners
References
Radley, D., June 2025 “Ancient ritual spear from Japan’s sacred island reveals East Asia’s earliest gold-inlaid sheath”, Archaeology News Magazine, June 21, 2025. Available at: https://archaeologymag.com/2025/06/ancient-ritual-spear-from-japans-sacred-island/
Arkeonews, June 2025. “Intricate Design Revealed on 1100-Year-Old Gold-Inlaid Ritual Spear from Japan’s Island of the Gods”. Available at: https://arkeonews.net/intricate-design-revealed-on-1100-year-old-gold-inlaid-ritual-spear-from-japans-island-of-the-gods/
Okinoshima Heritage. June 2025. New findings on the "gilt bronze spear sheath," a National Treasure unearthed at Okinoshima Island. Available at: https://www.okinoshima-heritage.jp/topics/detail/481
