Yoshinogari: A Great Moated Settlement of the Yayoi Period

The Yayoi period, which ran from about the fifth century BCE to the third century CE, is described by Yoshinogari Historical Park as the time when rice-farming culture began in Japan and settled life took root. Among the sites of this age, the park calls Yoshinogari in Saga Prefecture a site of extremely high academic value.

Over about 700 years, a cluster of small villages on a low hill grew into a vast community ringed by deep ditches. Remains from every phase of the Yayoi period have been found there, so the site shows step by step how society changed. This article follows Yoshinogari from its rediscovery in the 1980s through its rise and its end, and then to the historical park that stands on it today.

A site found again

Yoshinogari lies on a long, narrow terrace that runs from the southern foot of the Sefuri Mountains down toward the Saga Plain. The site spreads across what are now Kanzaki City and Yoshinogari Town. The park describes it as the largest archaeological site in Japan.

Researchers had long known that important remains lay here, and reports on the site appeared as early as 1934. The turning point came with a plan for industry. In February 1982 the Yoshinogari terrace was provisionally chosen as the top candidate site for a new Saga Prefecture industrial park.

Surveys then showed that about 58.3 hectares of the area held buried remains. The planned park was reduced from about 80 to 67.7 hectares; 6 hectares were set aside as green space to protect the remains, and 30 hectares were to be fully excavated and recorded before construction. Full-scale excavation began in late May 1986.

According to the park, the work confirmed that Yoshinogari was the largest moated settlement of the Yayoi period in Japan. Remains of buildings that recalled the land of Yamatai, as described in the Chinese Records of Wei, drew nationwide attention.

Yoshinogari was designated a national Historic Site in 1990. The Agency for Cultural Affairs' heritage database describes it as a large moated settlement essential for understanding the growth of powerful chiefs and the formation of early "countries" in the Yayoi period.

Surveys by the Saga Prefectural Board of Education showed that the settlement measured about 1 kilometer from north to south and 600 meters from east to west, covering about 40 hectares. Because the changes in the settlement and its graves could be traced from the Early to the Late Yayoi period, it was raised to a Special Historic Site in 1991.

From village to "kuni"

The park divides the story into three stages. In the Early Yayoi period (fifth to second century BCE), small villages were scattered across the hills.

Before long, a settlement surrounded by a ditch appeared on the southern part of the hill. The park sees in this the first signs of a change from mura (village) to kuni (country).

In 1999 excavators found part of what may be the oldest moat at Yoshinogari, at the southern tip of the hill. In the Early Yayoi period this settlement grew into a moated village of about 2.5 hectares.

Its ditch held pottery, stone tools, shells from the Ariake Sea and animal bones. Nozzles for bellows and ladles used in casting bronze were also found, and the park thinks that bronze casting began here during the Early Yayoi period.

In the Middle Yayoi period (second century BCE to first century CE), a great outer moat was dug around the whole southern hill, enclosing an estimated 20 hectares or more. Mound graves for chiefs and many jar-burial cemeteries appeared.

Inside the settlement, living areas and storage areas were kept apart. Finds include a wooden object thought to model an ocean-going boat and a few fragments of plain pottery of Korean type.

As the settlement grew, its defenses became stronger. The park reads this as a sign that conflict was becoming more intense.

In the Late Yayoi period (first to third century CE), the settlement expanded northward and became, in the park's words, the largest moated settlement in Japan, covering more than 40 hectares. Two special areas were enclosed by inner moats. The North Inner Enclosure, with watchtowers and a large ritual hall, is thought to have been the chief's residence and a place of ritual.

The South Inner Enclosure is thought to have housed people of high rank. To the west stood a group of raised-floor storehouses that gathered the goods of the kuni and may have served as a market.

With many people living behind moats, palisades and watchtowers, crafts such as bronze, iron and cloth, and a possible market, the park describes the settlement at this stage as the central settlement of a kuni that could well be called a Yayoi city.

Moats and graves

At its height, the outer moat ran for about 2.5 kilometers. The park explains that no traces of standing water have been found in the moats, so at Yoshinogari the word for moat is written with a character meaning a dry ditch. The deepest part found so far is about 3.5 meters deep and 6.3 meters wide; because the top has been worn away, the park estimates that it was once about 4.5 meters deep and 7 meters wide.

One study cited by the park estimated that digging a moat 2.5 kilometers long, 7 meters wide and 3 meters deep would have taken 100 people about 495 days, not counting the banks and palisades. The park thinks the outer moat was built mainly for defense against outside enemies, while the inner moats mainly divided the settlement into areas with different roles.

Burials tell another part of the story. In the Middle Yayoi period, jar burials that had been scattered were gathered into a long line of graves stretching for about 600 meters.

More than 3,000 burial jars and over 350 other graves have been found. The park notes that jar burial was a custom distinctive to the Saga and Fukuoka area.

North of the North Inner Enclosure lies the large North Mound Grave, where jar burials held bronze daggers and glass tube beads. The park sees in it signs of stronger social rules and growing differences in rank. A hilted bronze dagger, glass tube beads and other finds from the site are national Important Cultural Properties.

The end of the settlement

By the middle of the third century, at the very end of the Yayoi period, the moats around the settlement had largely filled in, and the park thinks the inner enclosures had lost their function. Around the same time, four keyhole-shaped mounded tombs with square rear parts were built on the hill near the South Inner Enclosure. The southern part of the hill seems to have changed from a place where people lived into a place where people were buried.

Was it Yamatai?

Places to visit

Yoshinogari Historical Park* (Yoshinogari Town and Kanzaki City). In 1992 the national government decided to develop the site as a national park, and a prefectural park was laid out around it. Part of the park opened in April 2001, and as of July 2024 about 106.9 hectares were open.

The park reconstructs the settlement as it was in the latter half of the Late Yayoi period, around the third century. To protect the remains, at least 30 centimeters of soil was laid over them, and buildings were reconstructed directly above the places where they once stood. The moats were rebuilt to their original depth and width on top of at least 50 centimeters of fill.

At the North Mound Grave, temperature and humidity are kept constant, and visitors can see the remains themselves. Please check the park's official website for opening hours and admission before visiting.