A Rich Natural Environment That Supported a Permanent Settlement
The Sannai Maruyama Site is located on a river terrace approximately 20 meters above sea level, on the right bank of the Okinate River, which flows toward Aomori Bay.
Behind the settlement are gentle hills extending from the Hakkōda Mountains. During the Jōmon period, the surrounding landscape included extensive deciduous broad-leaved forests, with trees such as chestnuts and walnuts.
The settlement was also relatively close to coastal and river-mouth environments, providing access to abundant aquatic resources. Fish and shellfish supplemented the food available from forests and land.
Living Between the Mountains, Rivers and Sea
This combination of resources was particularly favorable for a settled community. The inhabitants could obtain food and materials from mountains, forests, rivers, and the sea without relying on a single source.
The evidence discovered at Sannai Maruyama suggests that this rich environment played an important role in allowing the settlement to flourish for such a long period.
For modern visitors, the site offers an opportunity to think about how people thousands of years ago understood and made use of their surrounding environment without the technologies of modern agriculture and industry.
The Discovery and Preservation of Sannai Maruyama
The existence of the Sannai Maruyama Site had been known since the Edo period, but large-scale archaeological research did not begin until 1992.
The excavation was initially carried out in preparation for the construction of a prefectural baseball stadium. As researchers continued digging, however, they uncovered an astonishing number of archaeological remains, including more than 700 pit dwellings and the remains of enormous post-built structures.
The Discovery That Changed the Site’s Future
In 1994, archaeologists discovered the remains of a remarkable six-post structure made from enormous chestnut trees with trunks approximately one meter in diameter.
The discovery demonstrated the extraordinary archaeological importance of the site. Construction of the planned baseball stadium was subsequently canceled, and the decision was made to preserve Sannai Maruyama rather than destroy the remains.
Excavation, preservation, research, and public presentation have continued ever since. Today, Sannai Maruyama is one of Japan’s leading archaeological parks, where visitors can experience the results of ongoing research while walking through a landscape reconstructed from archaeological evidence.
The Structure of a Large Jōmon Settlement
The settlement covered an enormous area of approximately 35 to 40 hectares. Archaeological investigations have revealed a carefully organized community containing a wide variety of structures.
These include pit dwellings, post-built structures, raised-floor storage buildings, large pit dwellings, roads, storage pits, burial areas, and mounded refuse or activity areas.
A Large Pit Structure for Community Activities
One of the most impressive discoveries is a large pit dwelling measuring approximately 32 meters long and 10 meters wide.
Its enormous size suggests that it was not an ordinary family home. Researchers believe it may have been used as a gathering place, communal workspace, or for other activities involving larger groups of people.
A Carefully Planned Road
A road approximately 12 meters wide ran through the center of the settlement. Rows of neatly arranged burial pits have also been discovered.
These features suggest that Sannai Maruyama was not simply a collection of individual houses scattered across the landscape. Instead, the settlement appears to have had planned spaces and a degree of social organization.
For this reason, the site has played an important role in changing the way researchers understand Jōmon society. The Jōmon people were once sometimes portrayed as simple hunter-gatherers, but archaeological evidence from Sannai Maruyama reveals a much more complex society.
The Six-Post Structure – An Achievement of Jōmon Architecture
The six-post structure is one of the most iconic features of Sannai Maruyama. Six enormous chestnut posts were arranged in a carefully measured pattern, with each post measuring approximately one meter in diameter.
What is particularly fascinating is the precision of the postholes. Their spacing and depth were remarkably consistent, suggesting that the builders possessed sophisticated knowledge of measurement and construction.
Evidence of a Shared Unit of Measurement
The distance between the posts is approximately 4.2 meters, which corresponds to multiples of about 35 centimeters. This has led researchers to suggest that the Jōmon people may have used a standardized unit of measurement—sometimes informally described as a possible “Jōmon measure.”
Although the exact purpose of the structure remains uncertain, various interpretations have been proposed. It may have served as a lookout, ceremonial building, or facility connected with important community activities.
A reconstructed three-level version now stands at the site, giving visitors a sense of the impressive scale of Jōmon construction.
Artifacts Reveal a Wide World of Jōmon Life
The archaeological discoveries at Sannai Maruyama are extraordinarily diverse. Excavations have produced pottery, stone tools, clay figurines, stone objects, wooden artifacts, bone and antler tools, lacquerware, and woven baskets.
Nearly 2,000 excavated objects have been designated Important Cultural Properties of Japan, demonstrating the exceptional importance of the archaeological collection.
Trade Networks Reaching Far Beyond Aomori
Some of the most fascinating discoveries are materials that could not have originated locally. These include jade from the Itoigawa area, obsidian from distant regions, amber, and asphalt.
The presence of these materials indicates that the people of Sannai Maruyama participated in extensive exchange networks. Goods and raw materials traveled considerable distances, demonstrating that Jōmon communities were connected to other settlements across Japan.
Some artifacts also show similarities with cultural materials associated with the Asian continent, providing further evidence that the people of prehistoric Japan were part of a much wider world of interaction.
Food and Plant Use – More Than Hunting and Gathering
Analysis of animal bones and plant remains has revealed a remarkably varied diet at Sannai Maruyama.
The inhabitants used animals such as deer, wild boar, Japanese hare, and flying squirrels, as well as fish and shellfish. Large quantities of nuts, particularly chestnuts and walnuts, have also been discovered.
Evidence of Chestnut Cultivation
One particularly important discovery concerns chestnuts. DNA analysis suggests that chestnut trees may have been deliberately cultivated or managed by the inhabitants.
This evidence challenges the idea that Jōmon communities simply collected whatever nature happened to provide. Instead, people appear to have actively managed useful plants and landscapes to secure reliable sources of food.
Remains of annual plants such as perilla, bottle gourd, and beans have also been found, providing further evidence of plant management and possible cultivation.
Together, these discoveries show that Jōmon life involved a sophisticated relationship with the natural environment, combining hunting, fishing, gathering, plant management, and possibly cultivation.
Spiritual Life and Rituals
The people of Sannai Maruyama also left behind evidence of a rich spiritual and ceremonial culture.
Clay Figurines and Mounded Areas
More than 2,000 clay figurines have been recovered from large mounded areas within the settlement. Their presence suggests that rituals and ceremonies were conducted over a long period.
Among the most distinctive objects are flat clay figurines. Their forms differ from the more three-dimensional clay figurines associated with later periods of Jōmon culture and represent a distinctive artistic tradition of Sannai Maruyama.
Although archaeologists cannot know exactly what each figurine meant to the people who created it, these objects provide an important glimpse into the spiritual world of the Jōmon community.
Jōmon Jiyūkan – A Gateway to Jōmon Culture
Near the entrance to the archaeological site is the Jōmon Jiyūkan, an information and exhibition facility where visitors can learn more about the discoveries made at Sannai Maruyama.
Explore the Sanmaru Museum
The permanent Sanmaru Museum displays approximately 1,700 archaeological artifacts, including Important Cultural Properties. Exhibits introduce visitors to everyday life, technology, food, beliefs, and artistic expression during the Jōmon period.
The museum is particularly useful for visitors who are unfamiliar with prehistoric Japanese history. Rather than simply displaying artifacts, it helps explain how researchers use archaeological evidence to reconstruct the lives of people who lived thousands of years ago.
Try a Jōmon Craft Experience
Hands-on programs are also available, including activities such as making magatama beads and creating small clay figurines.
These activities provide an enjoyable way for both children and adults to experience aspects of Jōmon craftsmanship. Instead of simply looking at objects behind glass, visitors can gain a better appreciation of the skill and effort required to create them.
Explore the Site with a Guide
Visitors who want to understand the archaeological remains in greater depth can join a volunteer-guided tour.
A typical guided tour takes approximately one hour. Guides explain the major discoveries, reconstructed buildings, settlement layout, and the latest findings from archaeological research.
For international visitors, a guided explanation can make the ruins considerably easier to understand, especially because many of the structures are represented by foundations or reconstructed buildings rather than complete original structures.
Combine Sannai Maruyama with the Aomori Museum of Art
Another major attraction is located immediately next to the archaeological site: the Aomori Museum of Art.
The museum’s architecture was itself inspired by the excavated landscape of Sannai Maruyama. Its white, geometric spaces evoke the layers of earth and trenches created during archaeological excavation.
Visiting both attractions creates an especially interesting cultural experience. At Sannai Maruyama, visitors encounter the material remains of a society that lived thousands of years ago. At the Aomori Museum of Art, they encounter contemporary interpretations of art, identity, and human creativity.
Together, the two sites create a fascinating journey connecting prehistoric Jōmon culture with contemporary Aomori.
Access to the Sannai Maruyama Site
By car, the site can be reached in approximately 20 minutes from the Aomori Interchange or Aomori-Chūō Interchange via National Route 7.
Visitors using public transportation can also reach Sannai Maruyama by bus from Shin-Aomori Station and Aomori Station, making the site relatively convenient to include in an Aomori sightseeing itinerary.
Conclusion – Step into the World of Jōmon Japan
The Sannai Maruyama Site offers an extraordinary opportunity to encounter the world of prehistoric Japan.
More than 5,000 years ago, people established a large and long-lasting settlement here, making use of the abundant resources of the surrounding forests, rivers, and sea. Their homes, roads, storage facilities, burial areas, monumental structures, tools, pottery, ornaments, and clay figurines reveal a society far more sophisticated and interconnected than the simple image of prehistoric life might suggest.
The enormous six-post structure demonstrates impressive construction skills, while jade, obsidian, amber, and other imported materials reveal extensive exchange networks. Plant and animal remains provide clues about a diverse food culture and sophisticated management of natural resources, while thousands of clay figurines offer glimpses into the spiritual life of the community.
Today, Sannai Maruyama allows visitors to walk through this remarkable history. By exploring the archaeological remains, visiting the Jōmon Jiyūkan, taking part in a traditional craft experience, and combining the visit with the neighboring Aomori Museum of Art, travelers can experience the deep cultural layers of Aomori from ancient Jōmon society to contemporary art.
For anyone interested in Japanese history, archaeology, architecture, traditional culture, or the relationship between people and nature, Sannai Maruyama is an essential destination in northern Japan and one of the most fascinating places to discover Japan’s prehistoric past.