Restored Hachiman-zuka Kofun. The surface of the mound is covered by tonnes of rounde stones and cyrindrical haniwa are placed on the rim of each terrace. A group of 54 human and other figures lined up on the inner bank tell stories related to life of the person buried in the tumulus.
In the background Mt. Haruna is seen. Its highest peak appears just left to the square part of the tumulus, though it looks lower than other peaks.

Kofun in Gunma
- how to find truth between quiet tumuli and history records

As mentioned in another article, Gunma Prefecture has, by far, the largest number of old large-scale burial mounds, namely Kofun, in the Kanto region. In Japan's first history book, Nihon Shoki, as well as in Kojiki, members of a powerful clan "Kamitsu-Keno" are referred as having played major roles in the wars on the Korean Peninsula or the battle against Emishi (1). Their clan name, "Kamitsu-Keno" derives from the area name where they lived and it roughly corresponds to the present Gunma Prefecture.

(1)People who lived in the north of Japan who did not obey to the Yamato administration were called "Emishi". Though the same Chinese characters are used they are not identical with "Ezo".

Three little girls (haniwa)
- the most charming finding at Watanuki Kan-non-yama Kofun
In Gunma Prefecture, especially in the area at the eastern and southern foot of Mt. Haruna and Mt. Akagi, the present Takasaki City and Maebashi City, once the strong hold of Kamitsu-Keno clan, many new discoveries have been made in recent years as the field survey has progressed. In the fall of 2020, more than 3,000 items, which had been excavated from the Watanuki Kan-non-yama Kofun, were designated as national treasures. I therefore decided to visit the Gunma Prefectural Museum of History, which displays the excavated national treasures, and the Kamitsukeno-sato, which is known for restoring a tumulus to its original appearance.

According to the periodization of the Japanese history, the Yayoi Period lasted from the 5th century BC (2) to the middle of the 3rd century AD. In the Yayoi Period full-scale rice cultivation was introduced in Japan and many small countries were formed. Following the Yayoi period, the Kofun period began, when the Yamato court gradually integrated Japan, whereby the scale and design of tumuli were regulated to express the closeness of people to the Yamato court and the hierarchy among them.

(2)In recent years, it has been proposed that the beginning of the Yayoi period should be traced back to the 10th century BC in relation to the evaluation of carbon dating, and discussions continue.

Since rice cultivation came from the continent, the spread to the eastern part of Japan was delayed. It seems that the rice cultivation first came into the Gunma Prefecture from the Japan Sea coastal area through the present Nagano Prefecture and started as late as in the 2nd century AD at the foot of Mt. Haruna. In those days, people had their dwellings on the plateau and cultivated paddy fields in the nearby valleys. They did not use the large wetlands, which seem to be more suitable for rice cultivation today, because they were not able to control large-scale irrigation.

Images of two types of front-square kofun

Zenpou-kouhou fun
(Front and rear-square burial mound)
Symbol of anti-Yamato coalition?
Zenpou-kouen fun
(Front-square and rear-rounded burial mound)
The Yamato court built the Hashihaka Kofun in the latter half of the 3rd century and started to grasp hegemony over the entire Japan. A little later, in the 4th century, firstly front and rear-square burial mounds and then front-square and rear-rounded burial mounds began to be constructed in the Gunma Prefecture. This coincides with the time when a large amount of earthenware of the Tokai region style flowed in, the paddy fields were constructed in the vast low-land from the eastern part of Takasaki City to the southern part of Maebashi City and this low-land group and the indigenous group on the plateau cohabitated for a while without mixing each other.

The debate continues on whether this phenomenon should be regarded as the influx of culture or whether people flowed in with the culture. In this connection, it is interesting to note, Nihon Shoki reports that the tenth Emperor Sujin ordered his prince "Toyoki Irihiko" to rule the eastern country and his descendants became Kamitsu-Keno clan. On the other hand, some people believe that the reason why the front and rear-square burial mounds were first adopted as the standard for large burial mounds is that it was a common denominator of the countries under the influence of the Yamato's opponent "Kunu" which should have existed in the Tokai region.

The Ota Tenjin-yama Kofun, which is thought to have been built in Ota City in the eastern part of Gunma Prefecture in the first half of the 5th century, is a 210-meter-long front-square and rear-rounded Kofun and is the largest of this type in East Japan. After that, the Keno clan seems to have been split into two groups: Kamitsu-Keno in the present Gunma and Shimotsu-Keno in the present Tochigi. A large-scale tumulus comparable with the Ota Tenjin-yama Kofun was never built again.

Some important places in the old Kamitsu-keno area, western part of the present Gunma Prefecture

According to the view of archaeologist Toru Wakasa, Ota Tenjin-yama Kofun adopted the design of the tumuli of the Furuichi Kofun cluster in Habikino City, Osaka Prefecture and is half the size of the largest of the cluster, the Emperor Oujin's tumulus. After Ota Tenjin-yama Kofun, this design became the standard adopted by the chiefs in the region who insisted to be the legitimate successors of the legendary founder of the clan. So, the tumuli of the Iwahana Kofun cluster on the bank of the region's main stream Ino-River all follow the same design in the smaller scale. Their successors, the tumuli of the Hodota Kofun cluster, which are located along the Ino-river upwards, also adopted the same design. Finally, the same standard was applied to the Watanuki Kan-non-yama Kofun, which was built in a corner of the Iwahana Kofun cluster in the latter half of the 6th century. The relocation of the tomb sites took place within the Ino River basin, which was the territory covered by the chiefs buried in those Kofun.

Items discovered in the burial chamber of Watanuki Kan-non-yama Kofun

horse harness

belt with tiny bells

Stone coffin of the Hachiman-zuka Kofun
In this Ino River basin, a ruin that is thought to have been the residence of chiefs who were buried in the nearby tumuli of the Hodota Kofun cluster, has also been excavated. Unfortunately, the site has already been backfilled and cannot be seen, but this area was covered by volcanic ash or pumice due to the two eruptions of Mt. Haruna, first in AD500 and in AD550. Therefore, the excavated villages and tombs have kept the original appearances very well, just like Pompeii in Italy. A little further north, a man was discovered wearing a very exclusive armor. He might have tried in vain to stop eruption, the angry outburst of the mountain god, and fell into a pyroclastic flow 1600 years ago. If the eruption hadn't taken place, he would have been buried in one of the nearby tumuli at that time.
In case of the Hachiman-zuka Kofun, not only the burial mound but also a group of human haniwa lined up on its inner bank have been precisely restored. Due to the mudflow of volcanic ash from the eruption of AD500 shortly after the completion of the burial mound kept them all in good conditions and the exact appearance at that time came to be known to the researchers.
Seven different scenes are displayed with 54 figures. The front-right large figure is the chief who was buried in this grave mound. He there leads a long line of armed horses, which simbolizes his military capability. In all other scenes the chief plays the central role.
Haniwa were placed since the early Yamato burial mounds, firstly they were simple cylindrical haniwa, then house-shaped and equipment haniwa. Waterfowl and water-conducting haniwa were placed for the first time at the end of the 4th century in the Furuichi burial mounds, and finally in the first half of the 5th century groups of people's haniwa started to be placed. It is therefore natural that the tumuli of the Hodota Kofun cluster, which were constructed around 500 AD, were equipped with human shaped haniwa. When Watanuki Kan-non-yama Kofun was built later in the same century, a wide variety of haniwa were used.

By that time, haniwa were installed not only in the tombs of the chief class people but also in the tombs of lower-ranking members. In order to meet a large demand for haniwa, a few factories for haniwa production were established in the area, and skilled craftsmen became involved in manufacturing. The ancestors living in this area must have had special affection to haniwa.