Futagozuka Kofun: A Late Keyhole Tomb that Whispers of Yamato and Kibi
Rising quietly from a wooded hilltop in the eastern reaches of Hiroshima Prefecture, Futagozuka Kofun (二子塚古墳) is one of Japan's most intriguing burial mounds. Built around fourteen hundred years ago, it is among the very last large keyhole-shaped tombs ever constructed in western Japan—a final, ambitious statement from a culture on the cusp of transformation. Beneath its mossy mound lie two stone chambers, one of which stretches nearly fifteen meters into the hillside, holding clues to the political tides that swept across the Inland Sea on the eve of Japan's classical age.
Designated a National Historic Site in 2009, Futagozuka offers something rare among Japan's ancient tombs: a sense of intimacy. There are no ticket gates, no crowds—just a forested path, a panel explaining what you are about to see, and the sudden, hushed presence of a chamber that has stood here since the dawn of the seventh century.
Historical Background
The Kofun period (roughly the 3rd to 7th centuries CE) takes its name from the enormous earthen tombs—kofun—built across the Japanese archipelago for the ruling elite. The most prestigious of these tombs were shaped like a keyhole when viewed from above: a circular rear mound joined to a trapezoidal front. This distinctive form, known as a zenpō-kōen-fun, served not only as a tomb but as a powerful symbol of allegiance to the emerging Yamato court based in what is now the Nara and Osaka region.
By the late sixth century, however, the age of monumental keyhole tombs was drawing to a close. Smaller circular tumuli became the norm, and the political order was shifting toward a more centralized imperial state. It was precisely at this moment of transition that Futagozuka Kofun appeared in the Bingo region—a place where, curiously, no keyhole tombs had been built during the period when they flourished elsewhere. Its sudden emergence has fascinated archaeologists ever since.
Between 2002 and 2005, the Fukuyama City Board of Education conducted extensive excavations that revealed the mound's full scale and refined construction. The results not only confirmed its national significance but also brought to light remarkable artifacts that connect this remote hillside to the wider currents of Japanese history.
Why It Was Designated a National Historic Site
Futagozuka Kofun was first protected as a Hiroshima Prefectural Historic Site in 1948 and elevated to National Historic Site status on July 23, 2009. Three qualities, in particular, justify its place among Japan's most important archaeological monuments.
A late example in a culture's final chapter
Among keyhole tombs in western Japan, Futagozuka stands out as one of the very last to be built. Its construction in the late sixth to early seventh century marks the closing moments of a tradition that had shaped the landscape of Japan for nearly four hundred years.
Connections with the Kinai heartland
The stone coffin inside the main chamber was not made from local Bingo stone. Instead, it was carved from Tatsuyama-ishi, a tuff quarried in distant Harima (modern Hyōgo Prefecture)—the same material favored by elites in the Kinai region around the Yamato court. Both the coffin's material and the chamber's architecture point to direct ties between this hill in Hiroshima and the centers of political power far to the east.
A window onto Yamato–Kibi politics
The Kibi region (covering today's Okayama and eastern Hiroshima) was historically one of the strongest rivals to the Yamato court. Futagozuka's sudden appearance in Bingo—on the periphery of the old Kibi heartland—is widely interpreted as evidence of Yamato's careful diplomacy with the powerful families surrounding Kibi. The tomb thus stands as a tangible record of the political reshaping of western Japan on the threshold of the classical era.
Highlights and Things to See
The mound itself
The keyhole-shaped mound measures sixty-eight meters in total length—the largest tomb of its period in Hiroshima Prefecture. The rear circular section is forty-one meters across and roughly six and a half meters high, while the front rectangular portion stretches twenty-seven meters wide and four meters tall. A surrounding moat between 1.6 and 4 meters wide gives the entire structure a total length of 73.4 meters. Walking around the mound today, visitors can clearly trace this graceful keyhole silhouette through the surrounding woodland.
The great stone chamber
The crown jewel of the site is the horizontal stone chamber in the rear mound. Measuring 14.9 meters from end to end, it ranks among the largest in the Kibi region and is the longest within Hiroshima Prefecture. The burial chamber itself is 6.8 meters long, 2.1 to 2.6 meters wide, and 3.3 meters high; an 8.1-meter approach passage leads visitors into its hushed interior. The chamber walls are built of granite, with massive side stones leaning inward and a single great slab capping the rear. The whole construction conveys an almost cathedral-like sense of permanence. Please note: the rear stone chamber is not normally open to the public, and advance arrangements through the Fukuyama City Cultural Property Office are required for entry.
Two chambers, one mound
Unusually, Futagozuka has a second horizontal stone chamber in its front rectangular section. Though long since damaged—its ceiling stones and many wall stones removed in later eras—archaeological work has shown it was a substantial structure of about 12.6 meters in length. The presence of two large chambers in a single mound suggests that more than one important figure was honored here.
The twin-dragon sword pommel
Among the grave goods recovered from the rear chamber, none has captured imaginations like the gilt-bronze sword pommel adorned with twin dragons. Cast in a vivid, sculptural style, the two dragons each grip a sacred jewel in their mouths and are unified by a delicate dorsal fin—a design that is, to date, without parallel anywhere in Japan. Other finds include Sue and Haji earthenware, iron weapons, and horse trappings, painting a picture of a wealthy, well-connected occupant.
Layered earth and engineered foundations
Excavation revealed that the mound was built using a sophisticated layered-earth technique. Four distinct types of soil—reddish brown, black, gray, and yellow—were packed in alternating layers to give the structure extraordinary strength. The builders also worked in two clear stages, creating an inner mound first and then expanding outward, allowing them to support the weight of the great stone chamber as it was assembled.
Visitor Information
Futagozuka Kofun sits within the Fukuyama Kofun Road (福山古墳ロード), a network of marked walking trails developed by the city and local heritage volunteers to connect the area's many ancient sites. The mound itself can be visited freely at any time during daylight hours; only entry into the stone chamber requires advance permission.
Sturdy walking shoes are recommended, as the approach involves a short uphill path through woodland. The site is at its most evocative in spring, when fresh green leaves frame the mound, and in autumn, when red and gold foliage gives the ancient earthworks a quietly painterly atmosphere.
Surrounding Attractions
The Fukuyama Kofun Road
A signposted walking course links Futagozuka with nearby sites including Saimyō-ji temple ruins, the Ikenouchi archaeological site, Takarazuka Kofun, Saimyō-ji temple itself, Gongen Kofun, and the Edo-period Hattori Daiike reservoir. A leisurely half-day allows you to follow the entire trail and experience how layers of history—prehistoric, ancient, and early modern—share this small corner of the Bingo plain.
Hiroshima Prefectural Museum of History
Located in central Fukuyama, the museum displays artifacts unearthed across Bingo, including materials from Futagozuka Kofun. A visit here makes an excellent companion to the site itself, offering close-up views of the twin-dragon sword pommel and other recovered objects.
Tomonoura
About forty-five minutes from Fukuyama Station, the historic port town of Tomonoura preserves an Edo-period harbor surrounded by sake breweries, stone lanterns, and weathered wooden houses. Its inspiring views are said to have influenced Studio Ghibli's "Ponyo on the Cliff by the Sea."
Fukuyama Castle
The reconstructed donjon of Fukuyama Castle stands directly in front of Fukuyama Station and houses a museum dedicated to the local domain's history—an easy stop before or after exploring the kofun.
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Q&A
- Can I go inside the stone chamber?
- The rear stone chamber is not normally open to the public for conservation reasons. Visitors wishing to enter must apply in advance to the Fukuyama City Cultural Property Office (Tel: 084-928-1278). The mound exterior can be visited freely.
- What makes Futagozuka different from other kofun?
- It is one of the latest large keyhole tombs built in western Japan, appearing suddenly in a region where such tombs had not been constructed during the kofun era's peak. Combined with its unusually large stone chamber and Kinai-style stone coffin, this makes it a key witness to the late sixth- and early seventh-century shift in political power.
- How long does a visit take?
- A focused visit to the mound takes about thirty minutes. Walking the full Fukuyama Kofun Road route, which links several nearby sites, requires three to four hours at a comfortable pace.
- Is there an admission fee?
- No. The site is open free of charge, year-round, during daylight hours.
- How do I get there from Fukuyama Station?
- Take the JR Fukuen Line from Fukuyama Station to Ekiya Station, a ride of about twenty-five minutes. The kofun is approximately a ten-minute walk from the station. Taxis are also available from Fukuyama Station for those preferring a direct route.
Basic Information
| Name | Futagozuka Kofun (二子塚古墳) |
|---|---|
| Location | Nakajima / Niiyama, Ekiya-cho, Fukuyama City, Hiroshima Prefecture |
| Designation | National Historic Site (designated July 23, 2009; previously a Hiroshima Prefectural Historic Site since September 17, 1948) |
| Type | Keyhole-shaped tumulus (zenpō-kōen-fun) |
| Date of Construction | Late 6th to early 7th century |
| Mound Length | 68 m (73.4 m including the surrounding moat) |
| Rear Circular Section | 41 m in diameter, 6.5 m high |
| Front Rectangular Section | 27 m wide, 4 m high |
| Main Stone Chamber | Horizontal chamber, 14.9 m total length (chamber 6.8 m long, 2.1–2.6 m wide, 3.3 m high; passage 8.1 m long) |
| Stone Coffin | Combination-type sarcophagus of Tatsuyama-ishi tuff from Harima (Hyōgo Prefecture) |
| Notable Finds | Gilt-bronze twin-dragon sword pommel, Sue and Haji ware, iron weapons, horse trappings |
| Management | Fukuyama City |
| Access | About 10 minutes on foot from Ekiya Station (JR Fukuen Line) |
| Admission | Free (advance application required for entry into the stone chamber) |
| Inquiries | Fukuyama City Cultural Property Office, Tel: 084-928-1278 |
References
- Futagozuka Kofun – Cultural Heritage Online (Agency for Cultural Affairs)
- https://bunka.nii.ac.jp/heritages/detail/140424
- Futagozuka Kofun – Fukuyama City Official Website
- https://www.city.fukuyama.hiroshima.jp/soshiki/bunka/64146.html
- Futagozuka Kofun – Fukuyama Tourism and Convention Association
- https://www.fukuyama-kanko.com/travel/tourist/detail.php?id=48
- National Designated Cultural Properties Database (Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/00003645
- Fukuyama Kofun Road
- http://kofunroad.mokuren.ne.jp/
Last verified: 2026.05.13