Imashirozuka Kofun: A Sixth-Century Royal Burial Mound in Japan
Site at a Glance
- Rating
- 4.2
- Popularity
- Low
- Country
- Japan
- Primary era
- Medieval
- External website
- Open
- Eras represented
- Classical, Medieval
- Civilizations
- Yamato
- Site type
- Burial
- Remains
- Burial Mound
On this page10 sections
History
Imashirozuka Kofun is a keyhole-shaped ancient Japanese burial mound in Takatsuki, Japan, constructed in the first half of the sixth century during the late Kofun period. It stands in the Mishima Plain of northern Settsu and belonged to the Mishimano Kofun Group. Among the largest mounds built during its period, it is regarded as the tomb of a major ruler associated with the Yamato regime, the early state centered in the Yamato region that developed into the Japanese imperial polity.
A Royal Tomb of the Sixth Century
The prevailing scholarly interpretation identifies the buried individual as Emperor Keitai, traditionally counted as the twenty-sixth emperor of Japan. This theory rests on the mound’s form, the dates of its haniwa, and comparisons with the Kojiki, Nihon Shoki, Engishiki, and other historical records. The identification remains a historical theory rather than an Imperial Household Agency designation.
A major royal tomb in the northern Kinai, the central region of ancient Japan around the imperial capitals, has been interpreted as evidence of a shift in political leadership. The tomb’s position in the Yodo River system, which connects the inland basins and plains of central Kansai, points to a change from earlier centers of power in Yamato and Kawachi, an ancient region in the eastern part of present-day Osaka Prefecture.
Imperial Identification and Official Status
A prewar committee of historians and archaeologists recommended Imashirozuka for inclusion as a mausoleum reference site. The Imperial Household Agency instead designates Ōta Chausuyama Kofun, about 1.3 kilometers to the west, as Emperor Keitai’s mausoleum. Ōta Chausuyama is generally dated to the mid-fifth century, earlier than the period associated with Keitai’s death.
Imashirozuka Kofun was designated a National Historic Site in 1958. The designation was expanded in 1991 to include the New Pond Haniwa Production Site and extended again in 2006 to cover the northern part of the kofun. Because the mound is not designated as an imperial mausoleum or mausoleum reference site by the Imperial Household Agency, it has remained available for archaeological investigation and general access.
Damage, Investigation, and Restoration
The mound was once thought to have been damaged when Oda Nobunaga built a fortress there during his 1568 invasion of Settsu Province against the Miyoshi clan. Excavation instead showed that much of the damage resulted from a landslide-like collapse triggered by the Keichō–Fushimi earthquake of 1596, which struck the Kyoto–Fushimi area.
Takatsuki began large-scale archaeological investigations in 1997 while preparing the site for development as a historic park. Work by the Takatsuki Municipal Center for Buried Cultural Properties continued annually, with excavation also recorded from 1997 to 2007. The investigations recovered a large haniwa assemblage and clarified the mound’s damage and former ritual installations. A seven-year restoration and landscaping project was completed in March 2011. Approximately 190 replica haniwa were reconstructed in the ritual area, while restored haniwa and related archaeological material are displayed at the Imashirozuka Ancient History Museum.
Remains
Imashirozuka Kofun consists of a central keyhole-shaped tumulus with a circular rear section and a trapezoidal front section. The mound is enclosed by inner and outer moats, with intervening ground forming part of a roughly 340-by-350-meter, bell-shaped precinct. Several smaller auxiliary burial mounds are associated with the principal tumulus. The site’s surviving arrangement also includes a ritual zone on the raised bank between the two moats and evidence connected with the nearby production of haniwa, fired-clay figures and architectural forms placed around or on burial mounds.
Central Tumulus and Moats
The central mound is approximately 190 meters long. Its keyhole plan joins the circular rear burial area to the trapezoidal front section, while the inner and outer moats encircle the mound. The raised strip separating the two water-filled moats is an inner bank, or levy. The precinct’s broad scale and the presence of associated auxiliary tumuli show how the principal burial mound was integrated into a larger funerary landscape.
Haniwa Ritual Zone
The haniwa ritual zone occupies the inner bank between the two moats. It extends approximately 62 to 65 meters from east to west and about 6 meters from north to south, making it the largest known haniwa ritual zone in Japan. At least 113 figures were found in rows or groups extending outward from the middle embankment for as much as 6 meters. The assemblage included houses, fences, lids, swords, a shield, a quiver, warriors, falconers, wrestlers, a male wearing headgear, seated men, shrine maidens, four-legged animals, chickens, and water birds. Their arrangement may represent the burial ceremony of a high-status individual, although that interpretation remains uncertain.
House-Shaped Haniwa
The house-shaped haniwa reach approximately 170 centimeters in height, roughly the height of a person, and are described as the largest examples of their type found in Japan. They depict buildings with hip-and-gable roofs, roof ornaments corresponding to chigi, or forked finials, and katsuogi, short logs set across a roof ridge. Cylindrical pillars represent raised-floor supports. Their open, elevated form has led to the interpretation that they may depict shrine architecture.
Earthquake Scar and Sarcophagus Fragments
Before site improvements, the center of the front section appeared to project in a broad arc of approximately 35 meters toward the inner moat. This feature led to the classification of the mound as a sword-diamond-shaped keyhole mound. Excavation established that the projection was a landslide scar caused by the 1596 earthquake, removing the basis for that classification. The front edge was made straight during subsequent improvements.
In 2016, stone formerly used in a nearby bridge was identified as possibly consisting of fragments from the kofun’s stone sarcophagus. The identification remains possible rather than certain.
New Pond Haniwa Production Site
The New Pond Haniwa Production Site is closely associated with Imashirozuka Kofun. It operated for approximately a century, from the mid-fifth to the mid-sixth century, and was one of the oldest and largest known haniwa production centers. Excavations identified three large workshops, 18 kilns, and a settlement for the craftspeople who made the figures.
