Model of Isedotai ruins (Isedotai Jomonkan)

[Kitaakita City, Akita Prefecture] 4 stone rings in one place. Isedotai Ruins, a mysterious ruin registered as a World Heritage Site   

Isedotai Ruins is a Jomon period ruin located in Kitaakita City, Akita Prefecture. Its most distinctive feature is the presence of four stone circles, and due to its well-preserved state, it has been designated as a national historic site, and is one of the World Cultural Heritage Sites , ``Jomon Sites in Hokkaido and Northern Tohoku.'' is registered in.


Stone circles are common throughout the world and were a place of prayer at the center of a village.

A major feature of the Isedotai ruins is that four stone rings were built in the same square. This is the only place in Japan where four of these were found in the same place.

A stone ring is a set of stones placed in a round shape, and similar types exist all over the world, including the world-famous Stonehenge in England. In Japan, they are often found from the Tohoku region to southern Hokkaido, and there are more than 20 large ones with a diameter of 30 meters or more. The largest and most famous stone ring is the 52m diameter Manza stone ring (located in Kazuno City, Akita Prefecture), which is part of the Oyu stone ring.

What were the stone circles built for? There are many theories, including houses arranged in a ring, graveyards, and celestial objects (such as sundials). There is a strong theory that it may have been.


Around 4,000 years ago, the area around the ruins was suitable for human habitation.

It is known that the Isedotai ruins were built relatively early in the late Jomon period (late early period). The Jomon period lasted for over 10,000 years, from about 15,000 years before the end of the Paleolithic period to about 2,400 years ago. These 10,000 years are the pioneer period (until approximately 11,000 years ago), early period (until approximately 7,000 years ago), early period (until approximately 5,000 years ago), middle period (until approximately 4,000 years ago), and late period (approximately 3,000 years ago). It is divided into three periods: the early (until about 2,400 years), and the late period (until about 2,400 years), which was followed by the Yayoi period, when farming was the center of life.

The Isedo ruins were built in the early part of the late Jomon period, which was a time when temperatures were close to today's and comfortable to live in, even though there were major climate changes such as ice ages and warming periods throughout the Jomon period. A deciduous broad-leaved forest spreads around the ruins, and fish such as salmon could be caught from the Yoneshiro River, and in autumn, chestnuts and acorns, which were the staple food, could be collected. Additionally, in winter, the leaves fall, making visibility better and ideal for hunting animals. Despite the cold and snowy winters, it is thought that they did not have to worry about food.


The Isedotai ruins were discovered in the Heisei era.

The Isedotai ruins are located on a river terrace at an altitude of 42 to 45 meters above sea level of the Yoneshiro River, a large river that flows through northern Akita Prefecture. Isedotai is a place name that means Isedo Hill (Tai), and it is said that there was a shrine called Isedo nearby, although it is unknown when.

Stone circles during excavation (2006) ©Kitaakita City

The Isedotai ruins were discovered in 1992 (Heisei 4) while surveying the access road planning site for Odate-Noshiro Airport, which opened in 1998 (Heisei 10), and full-scale construction began in 1994 (Heisei 6). As a result of extensive research, stone circles A and B were excavated the following year, and stone circle C was excavated in 1996. Therefore, in response to the voices of local residents and prefectural residents demanding preservation of the ruins, it was decided to detour the access road.

After that, excavations continued, including the remains of hotatebashira tatemono buildings (buildings with pillars embedded directly into the soil, rather than erecting pillars on the foundation), and earthen pit graves ( Graves where people were buried by digging holes directly into the soil) and postholes were found. Furthermore, in 2000 (Heisei 12), a fourth stone ring (stone ring D) was confirmed.

©Kitaakita City

Stone circle A remains unfinished even after 200 years

All four stone rings are over 30m in diameter, and the stones were brought from a river some distance away and placed in a large circle.

Stone circle A, the northernmost one, is slightly oval in shape and has a major axis of 32 m. There are 1,272 stones lined up, and there are more than 20 types of stones and a variety of colors. It is said that some of the stone masonry was planned to be surrounded by a double row of stones on the outside, but it was left unfinished.

A stone circle lined up with various stones from the riverbank ©Kitaakita City

Stone circle B, only partially excavated

Only part of the approximately 15m circle (arc) of Stone Ring B has been discovered. As a result of excavation, it is thought that for some reason only a portion of the structure was built, as no trace of it had been scraped away.


Stone ring C, the largest of the four, with a diameter of 45m

Stone circle C with a diameter of 45m. The lower half has not been excavated ©Kitaakita City

Stone circle D, which has high expectations for future excavations

Stone circle D is located in the southernmost part and is oval in shape with a major axis of approximately 36 m. It is believed that the stone circle was double-layered, but many parts of the stone circle do not retain their original shape, and like stone circle C, they were built on artificially leveled land. Only the northern half has been excavated.


Will it be abandoned after 200 years? Isedotai ruins full of mysteries

The stone rings at the Isedotai ruins are still shrouded in many mysteries. One of them is that some of the four pieces are unfinished. Stone circles are not built all at once, but take many years to complete, but the fact that they are abandoned unfinished indicates that people have moved away from the area. I am. According to excavation research, the period is said to be about 200 years. There are still many things we don't understand about the Jomon period, and we look forward to future research.


More than 13,000 artifacts were excavated from the ruins. Some are designated as tangible cultural properties of Akita Prefecture.

Excavated items thought to have been used in the festival ©Kitaakita City

Many pottery vessels, clay figurines, and stone tools have been discovered in and around the stone circles. Excluding fragments, 13,088 items were excavated, of which 280 items that still retain their original shapes have been designated as tangible cultural properties of Akita Prefecture.

The only plate-shaped clay figurine that has been completely restored ©Kitaakita City

Among the excavated items, countless clay figurine fragments were discovered in the earthen pit grave of stone circle B, and only one of these, the plate-shaped clay figurine, was able to be restored to its complete form. Its maximum height is 18.8cm, maximum width 13.0cm, and maximum thickness 1.5cm, and it is on display at the Isedotai Jomon Museum

Exhibition centered on plate-shaped clay figurines from “Isedai Jomonkan” ©Tabi Tohoku

The ``Isedotai Jomon Museum'' at the Isedotai ruins , and many excavated items are on display. A guidance video is also shown, and by visiting the site along with the ruins, you will be able to deepen your understanding of the World Heritage Isedotai ruins.

A large replica of the clay figurine that greets you at Isedai Jomonkan

Isedotai Ruins<Information>

  • Facility name: Isedotai Ruins/Isedotai Jomon Museum
  • Location: 100-1 Ogata Nakata, Wakigami, Kitaakita City, Akita Prefecture
  • Phone number: 0186-84-8710
  • Opening hours:
    • Isedotai Ruins/9:00-16:30
    • *Closed in winter from November to mid-April to preserve the stone circles.
    • Isedotai Jomonkan/9:00-17:00
  • Closed: Mondays (the next day if Monday is a public holiday), New Year holidays (December 29th to January 3rd)
  • Admission fee/exhibition viewing fee: Free
  • URL: Isedotai Jomonkan
  • access:
    • Railway/Akita Nairiku Jukan Railway Line: Approximately 5 minutes' walk from Jomon Ogata Station
    • Car: Approximately 10 minutes from Akita Expressway Isedotai IC

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