The Tsukamawari Kofun Group is an important archaeological site in Tatsumai-cho, Ota City, Gunma Prefecture. Dating from the Kofun period, the site provides valuable insights into the ancient communities, beliefs, and funerary traditions of the region.
Today, the site has been preserved as a kofun park surrounded by rice fields. Visitors can explore the reconstructed burial mounds and see replicas of haniwa clay figures, offering an accessible way to imagine the lives and rituals of people who lived here more than 1,500 years ago.
The burial mounds are believed to have been constructed from around the middle to latter half of the 6th century. They are thought to have served as burial sites for local leaders and influential community chiefs.
Among them, Kofun No. 4 is particularly well preserved. It has been designated a Historic Site by Gunma Prefecture, while the group of haniwa excavated from the mound has been designated an Important Cultural Property of Japan.
The Tsukamawari Kofun Group was formally identified during archaeological excavations carried out in 1977 in connection with a prefectural agricultural land improvement project. The investigation revealed seven burial mounds beneath the rice fields.
Although the area is now a flat agricultural landscape, during the Kofun period it is believed to have been a low plateau that gently sloped from northwest to southeast. Later, flooding and deposits of mud and sediment altered the landscape and gradually buried the ancient burial mounds.
Further excavations in 2010 uncovered another four burial mounds beneath a sediment layer associated with a major flood in 818. These discoveries suggest that additional ancient burial mounds may still remain in the surrounding area.
A total of 13 burial mounds have been identified at the Tsukamawari Kofun Group. Most are either keyhole-shaped mounds with a rounded rear section and a narrower front section, or circular burial mounds. Their typical diameters range from approximately 10 to 20 meters.
Many of the original mounds were leveled during agricultural development. However, portions of Kofun No. 3 and the entirety of Kofun No. 4 have been preserved and restored.
Kofun No. 1: A 26.1-meter-long scallop-shell-shaped burial mound, largely leveled.
Kofun No. 2: A 24-meter-long scallop-shell-shaped burial mound, largely leveled.
Kofun No. 3: A scallop-shell-shaped burial mound, with part of its front section preserved.
Kofun No. 4: A 22.5-meter-long scallop-shell-shaped burial mound that has been restored and preserved.
Kofun No. 7: A circular burial mound approximately 20 meters in diameter.
Groups of multiple burial mounds like this are known as clusters of kofun. They are thought to have served as burial grounds for members of powerful local families or communities.
Kofun No. 4 is the most significant mound in the Tsukamawari group. It was discovered during the 1977 excavation and has since been restored as part of the present-day kofun park.
The mound is a scallop-shell-shaped kofun measuring 22.5 meters along its central axis. The rounded rear section has a diameter of approximately 17.7 meters, while the front section is approximately 8.7 meters wide.
Two burial facilities were identified in the rear section, and they are believed to have contained stone coffin structures. However, no human remains or grave goods were discovered inside the coffins.
The most remarkable feature of Kofun No. 4 is the large number of haniwa clay figures discovered at the site. A total of 304 haniwa were recovered, including 253 cylindrical haniwa and 35 figurative haniwa.
The figurative haniwa depict a wide variety of subjects, including people, horses, swords, shields, and houses. They provide valuable information about ancient rituals and the social world of the Kofun period.
Some of the human figures are particularly detailed, including a woman presenting a cup, a man seated on a chair, and a person leading a horse. Their carefully modeled hairstyles and clothing offer a fascinating glimpse into the appearance and material culture of people living more than 1,500 years ago.
Cylindrical haniwa were arranged around the rear section of the mound, while swords and shields were placed alternately on the outer side.
Human and horse-shaped haniwa were positioned around the front section. Because their locations were recorded relatively clearly during excavation, the arrangement provides valuable evidence for understanding ritual practices associated with kofun burials.
Kofun No. 4 has been restored and developed as a historic kofun park. Replicas of haniwa have been placed around the mound based on their excavated positions.
The sight of cylindrical haniwa and human figures standing around the graceful scallop-shell-shaped mound gives visitors a vivid impression of what an ancient funerary ceremony may have looked like.
Walking through the park, visitors can imagine the beliefs, rituals, and social traditions of the people who built these monumental burial sites.
The central axis of Kofun No. 4 runs almost precisely in an east-west direction. The haniwa were also arranged facing toward the west, a layout that has been suggested to have a possible connection with the direction of the setting sun.
Although the exact meaning of this arrangement remains a subject of interpretation, such features provide intriguing clues about the religious beliefs and views of life and death held by ancient communities.
Ota City is particularly rich in ancient burial mounds. Approximately 1,200 kofun dating from the 3rd through 7th centuries have been identified in the city.
Among them is Tenjinyama Kofun, one of the largest keyhole-shaped burial mounds in eastern Japan. The concentration of large and sophisticated kofun demonstrates the importance of the Ota area during the Kofun period.
Haniwa are unglazed terracotta objects that were placed around the mounds and on the tops of burial mounds during the Kofun period, which lasted roughly from the 3rd to the 7th centuries.
The earliest haniwa were generally simple cylindrical forms. Over time, however, increasingly elaborate figurative haniwa were produced in the shapes of people, animals, houses, weapons, and other objects.
Haniwa are believed to have helped protect and define the burial mound and to have played symbolic roles in funerary rituals. Many also depict clothing, weapons, hairstyles, and aspects of daily life, making them important sources for archaeological and historical research.
Gunma Prefecture is one of Japan’s major regions for haniwa culture. More than 13,000 ancient burial mounds have been identified across the prefecture, and many have yielded haniwa.
One notable characteristic of the region is that haniwa production continued on a large scale even during periods when their production had declined in areas such as the Kinai region around present-day Nara and Osaka.
As a result, Gunma has preserved an exceptionally diverse collection of highly artistic haniwa, making the prefecture an important area for understanding the development of Japan’s Kofun culture.
Numerous haniwa have been discovered at burial mounds throughout Ota City, including the Tsukamawari Kofun Group. They include figures of people, horses, houses, weapons, and other objects, vividly conveying aspects of ancient society and ritual.
The Tsukamawari Kofun Group has produced numerous figurative haniwa, including human figures, horse-shaped figures, house-shaped figures, and representations of weapons and armor.
Among the discoveries are figures that appear to depict ritual scenes, such as a woman presenting a cup, a kneeling man, and a person leading a horse. The fine details of their hairstyles and clothing demonstrate the sophisticated craftsmanship of ancient haniwa makers.
Because the original positions of many of these figures were relatively well documented, the collection is especially valuable for studying the arrangement of haniwa and the rituals performed around ancient burial mounds. Many of the haniwa excavated from the Tsukamawari Kofun Group have therefore been designated Important Cultural Properties of Japan.
Gunma is also known for its remarkable collection of human-shaped haniwa. One of the most famous examples is the Keiko-Armor Warrior Haniwa, depicting a warrior dressed in armor.
This type of haniwa is an important source of information about armor, weapons, and military culture during the Kofun period. Because of its exceptional craftsmanship and historical importance, a Keiko-Armor Warrior Haniwa was designated a National Treasure of Japan, becoming the first haniwa to receive this distinction.
The ancient province of Kozuke, corresponding broadly to present-day Gunma Prefecture, was therefore an important center of haniwa culture. The high quality of surviving examples suggests that skilled haniwa craftsmen were active in and around the Ota area.
Many of the original haniwa excavated from the Tsukamawari Kofun Group are preserved and displayed at institutions such as the Gunma Museum of History and the Gunma Archaeological Research Foundation.
Seeing the original artifacts up close provides an opportunity to appreciate the artistic skill and cultural traditions of ancient communities.
At the Tsukamawari Kofun Group itself, visitors can see the restored burial mound together with replicas of the haniwa. The reconstructed setting makes it possible to imagine how these figures may have been arranged during ancient funerary rituals.
The haniwa discovered in Ota are far more than simple clay objects. They are valuable historical artifacts that preserve information about ancient society, religious beliefs, rituals, art, and daily life.
A visit to the Tsukamawari Kofun Group offers an opportunity to imagine how people more than 1,500 years ago built their burial mounds and conducted ceremonies to honor the dead.
The Tsukamawari Kofun Group is an important heritage site that brings the society and culture of the Kofun period to life. The restored Kofun No. 4 and its reconstructed haniwa arrangement provide a particularly vivid impression of ancient funerary traditions.
Set quietly among the rice fields of Ota City, the park offers a peaceful place to walk while discovering the archaeological heritage of Gunma.
When visiting Ota City, take a leisurely walk around the Tsukamawari Kofun Group and imagine the world of the people who lived here approximately 1,500 years ago.