The Tawayama Archaeological Site in Matsue, Shimane Prefecture, is one of the most unusual and intriguing archaeological sites from Japan’s Yayoi period. Occupied from the latter part of the early Yayoi period through the latter part of the middle Yayoi period, the site offers important clues about how people lived, worshipped, and organized their communities approximately 2,000 years ago.
Tawayama and the nearby Jingoda Archaeological Site are collectively designated as a National Historic Site under the name Tawayama-Jingoda Archaeological Site. Their unusual structures have attracted considerable attention among researchers studying Yayoi-period settlements in Japan.
The site was extensively investigated between 1997 and 2000 during archaeological excavations carried out in connection with the construction of Matsue City Hospital. One of the most remarkable discoveries was a series of three concentric moats surrounding the summit of the hill.
The largest sections of the moats were approximately 7 meters wide and 1.8 meters deep, making them exceptionally substantial for a Yayoi-period site. Constructing such large defensive ditches would have required a considerable amount of labor.
Yet the purpose of these moats remains a mystery. Unlike a typical Yayoi moat settlement, the main residential area at Tawayama appears to have been located outside the moats. The enclosed area at the center was surprisingly small, and only a few building remains have been discovered there.
This unusual arrangement raises an important question: why did the people of Tawayama invest so much effort in constructing enormous moats around an area that was apparently not used as their main residential zone?
The summit of Tawayama stands approximately 45 meters above sea level. A relatively flat area measuring about 10 meters from east to west and 30 meters from north to south occupies the top of the hill.
From here, visitors can enjoy broad views over Lake Shinji, central Matsue, and even Mount Daisen in the distance. The commanding location would have made the hilltop a highly visible and symbolic place in the ancient landscape.
Archaeologists discovered remains of buildings supported by five and nine posts on the summit. Postholes believed to represent fences were also found surrounding the area.
The arrangement of these structures has been compared with the possible origins of later Shinto shrine architecture. Although their exact purpose cannot be determined with certainty, they may have been associated with ceremonies, rituals, or other activities of religious or political significance.
These discoveries suggest that Tawayama was more than an ordinary settlement. The hilltop may have served as a special space where religious beliefs, community authority, and social symbolism came together.
The three moats surrounding the hilltop provide some of the strongest evidence that Tawayama had a special function. Approximately 3,000 sling stones were discovered at the bottoms of the moats, along with numerous weapons such as stone arrowheads and stone swords.
These finds indicate that the site had at least some defensive characteristics. The moats may have helped protect the central hilltop area from attacks or control access to it.
However, the lack of substantial residential remains inside the moats makes it difficult to interpret Tawayama simply as a military stronghold. Another possibility is that the moats helped separate a sacred or politically important central space from the surrounding settlement.
The site therefore provides a fascinating glimpse into the complex relationship between defense, religion, and authority in Yayoi-period society.
Among the artifacts discovered at Tawayama are pottery, stone tools, weapons, and an especially noteworthy stone inkstone. Inkstones from the Yayoi period are extremely rare in Japan, making this discovery particularly important.
The Tawayama example has been compared with an inkstone discovered at the Mitsumune-Ihara Archaeological Site in Fukuoka Prefecture. Its characteristics have also led researchers to suggest a possible connection with products from Lelang Commandery, an ancient Chinese administrative region located on the Korean Peninsula.
This possibility is significant because it suggests that people in the region may have been connected, directly or indirectly, with wider networks of exchange extending across the Korean Peninsula and East Asia.
The object once attracted attention as a possible example of Japan’s oldest writing-related evidence. However, subsequent analysis raised the possibility that the substance on the stone was not ink. Its interpretation is therefore treated cautiously today, but the artifact remains valuable evidence for considering the nature of Yayoi-period contacts with neighboring regions.
The Jingoda Archaeological Site lies approximately 500 meters south of Tawayama. Archaeological investigations conducted since 2017 have revealed features including moats dating to the early Yayoi period.
Both sites share an unusual characteristic sometimes described as a “moated vacant area”: the enclosed space was not primarily used for ordinary residential purposes. Their locations at different elevations suggest that the two sites may have functioned as related centers within the same regional community.
During the middle Yayoi period, Jingoda appears to have declined, while functions may have become concentrated at Tawayama. At around the same time, Tawayama’s moat system expanded to three rings.
This change provides important clues for understanding how the organization of local communities and the concentration of authority may have developed during the Yayoi period.
The Tawayama Archaeological Site was designated a National Historic Site in 2001 and is now preserved as Tawayama Historic Site Park.
At the summit, the positions of posts and fences have been reconstructed, allowing visitors to imagine how the ancient space may have been organized. Walking through the site while looking across the surrounding landscape offers a unique opportunity to connect the archaeological evidence with the natural setting that shaped the lives of people 2,000 years ago.
The hilltop is also a pleasant place for a short nature walk. The breeze from Lake Shinji and the expansive views across Matsue create a peaceful atmosphere, contrasting with the mysterious history hidden beneath the ground.
Tawayama is especially valuable because it challenges the familiar image of a Yayoi-period moat settlement. Rather than placing a residential community inside a defensive enclosure, the site appears to have separated a relatively empty and possibly special central area from the surrounding settlement.
The three concentric moats, weapons and sling stones, unusual hilltop buildings, possible ritual facilities, and rare stone inkstone all raise questions about the relationship between religion, defense, political authority, and international exchange in ancient Japan.
For visitors interested in Japanese history, Tawayama Historic Site Park offers something different from castles, temples, and traditional townscapes. Here, the remains are much older, dating back roughly 2,000 years to a time when Japanese society was undergoing major changes.
At the same time, the hilltop location provides beautiful views of Lake Shinji and Matsue. Standing among the reconstructed features and looking across the same landscape that ancient communities once inhabited is a memorable way to experience the distant past.
Tawayama Archaeological Site is a fascinating destination for anyone who wants to explore the mysteries of the Yayoi period and discover how archaeological remains can reveal not only how people lived, but also how they understood power, community, and the world around them.