Tsunozuka Kofun: A Northern Keyhole-Shaped Burial Mound in Japan
Site at a Glance
- Rating
- 4.4
- Popularity
- Very Low
- Country
- Japan
- Primary era
- Classical
- Eras represented
- Classical, Medieval
- Civilizations
- Yamato
- Site type
- Burial
- Remains
- Burial Mound
On this page7 sections
History
Tsunozuka Kofun is a keyhole-shaped burial mound in Japan, located in the Isawa area of Ōshū, Iwate. Constructed in the late fifth or early sixth century AD during the final phase of the Kofun period, it is the only example of its form in Iwate Prefecture and is regarded as the northernmost known keyhole-shaped kofun in Japan.
Construction and Cultural Setting
The planned form of Tsunozuka Kofun shows that it was deliberately built as a formal burial mound. The name and rank of the person buried there are unknown, and the mound does not appear in historical records. Its location is important because it marks the northern reach of Kofun-period culture into an area traditionally associated with the Emishi, peoples of northern Honshu who lived beyond, or resisted, the authority of the imperial state described in early Japanese records.
A large settlement dating from the same period lies about 2 kilometers northwest of the mound. Objects from that settlement indicate links with the Miyagi region and the Kuji area, and a connection between the settlement and Tsunozuka Kofun has been proposed. South of the mound, another keyhole-shaped kofun is not known until the Ōsaki area of northern Miyagi, approximately 70 kilometers away.
Investigation and Protection
Haniwa finds drew the attention of local researchers during the 1930s. The mound was excavated or investigated in 1935 and 1945, and archaeologists confirmed its keyhole-shaped plan in 1947. This identification brought particular attention to its position as the northernmost substantial example of the type.
Tsunozuka Kofun became an Iwate Prefectural Historic Site in 1957. Surveys and boundary investigations carried out by the Isawa Town Board of Education in 1974 and 1975, during preparations for agricultural land consolidation, confirmed further haniwa and fukiishi. The mound was designated a National Historic Site in 1985 because of its exceptional northern location.
Legend and Preservation
Local tradition connects the mound with a story about a wealthy man whose greedy wife became a great serpent and tormented farmers. Villagers supposedly bought a girl from the land of Matsuura as a sacrifice. When the serpent appeared, the girl read Buddhist scriptures and threw the text at it, causing the creature to return to the form of the wealthy man’s wife. The tradition says that the serpent’s horn was buried at Tsunozuka Kofun.
The same tradition held that disturbing the mound would bring a curse. This belief is said to have helped preserve Tsunozuka Kofun into the present.
Remains
Tsunozuka Kofun stands at approximately 76 meters above sea level on a low terrace of the Isawa alluvial fan, where the Isawa River joins the middle reaches of the Kitakami River in the southern Kitakami Basin. Its surviving earthwork measures about 43 to 45 meters in length and combines a two-tiered circular rear section with a projecting front section, creating the characteristic keyhole plan.
Mound and Moat
The circular rear section is approximately 28 meters in diameter and 4 meters high. The front projection faces south and is shorter and lower, measuring about 1.5 meters high, roughly 10 meters wide at its northern side and about 15 meters wide at its southern side. The mound has suffered heavy damage, and a large cedar was planted on the rear section at a later date.
A surrounding moat measures approximately 10 meters across beside the rear circular section and narrows to about 3 meters around the front projection. Its horseshoe-shaped plan contracts toward the southern end. The burial facility is presumed to have been placed beneath the level surface at the top of the mound.
Surface Covering and Haniwa
Fukiishi, stones laid over a burial mound to protect its earthen surface and give it a finished exterior, covered parts of Tsunozuka Kofun. Most excavated material consists of haniwa, clay figures and cylinders placed around or on burial mounds. The front section produced figurative examples representing people, animals, buildings and implements, while cylindrical haniwa came from the moat around the rear circular section. These objects are considered to have been made in the latter half of the fifth century.
The excavated haniwa and other finds are preserved and displayed at the Isawa Local History Museum within the Isawa Cultural Creation Center. In 1990, the excavated haniwa were designated Iwate Prefectural tangible cultural properties.
