Japan's Kofun Period: 160,000 Ancient Tombs Built by the Forgotten Tomb Builders

Forested Kofun burial mound surrounded by a moat

June

/ 2026

Getting your audio player ready...

During Japan's Kofun Period (250–538 AD), no fully centralized imperial state governed the archipelago, but a powerful Yamato polity was gradually consolidating authority over much of western Japan. Across the landscape rose enormous earthen tombs, many shaped like keyholes, surrounded by moats and clay haniwa figures. These kofun, meaning “old mounds” in Japanese, honored rulers and elite families whose authority rested on warfare, marriage alliances, ritual power, and control of regional networks. Centered in the Yamato region, this emerging political order helped lay the foundations for the later Japanese imperial system

Keyhole-shaped tomb Haze Nisanzai Kofun Aerial photograph 2007, (Geospatial Information Authority of Japan/Made based on National Land Image Information (Color Aerial Photographs), Ministry of Land, Infrastructure, Transport and Tourism (Japan)

The Period of Great Tomb Builders

According to the UNESCO report on the Japanese kofun, the organization has selected 49 kofun from the 160,000 in Japan to show evidence of “a highly sophisticated funerary system.” These special mounds are located on a plateau above the Osaka Plain. They show the differences in social classes through variations in size. Aerial views show intricate geometric shapes: keyhole, scallop, square, and circle. Designs using paving stones decorate tomb entrances. Terracotta haniwa figures were placed around the tombs as part of funerary rituals. Their exact purpose remains debated, though they may have marked sacred space, represented attendants, or served symbolic protective functions.

The construction of the kofun required exceptional technical skills in building earthworks. The Daisen Kofun, one of the largest tomb complexes in the world, honors Emperor Nintoku. Construction likely required the coordinated labor of thousands of workers over many years. Only an elite authority and political power could have organized such an architectural marvel.

Moat Surrounding a Kofun Burial Mound, Japan, (Hyppolyte de Saint-Rambert/CC BY 4.0)

7 Key Kofun

The Daisen Kofun is the largest kofun in Japan and one of the largest tombs in the world. Located in Sakai, it measures 486 meters long and is surrounded by moats. The Daisen Kofun is traditionally attributed to Emperor Nintoku, although archaeologists have not been permitted to excavate the central burial chamber, and the identification remains unconfirmed. It is part of the Mozu-Furuichi Kofun Group, a UNESCO World Heritage Site.
Hashihaka Kofun is believed to be one of the earliest giant keyhole-shaped kofun. It is located in Sakurai. Some researchers have proposed that Hashihaka Kofun may be the tomb of Queen Himiko, the third-century ruler mentioned in Chinese chronicles, although the identification remains controversial.
Ōjin Tennōryō Kofun is associated with Emperor Ōjin, and it is the second-largest kofun in Japan, measuring 425 meters long. It has the keyhole shape and several moats.
Richū Tennōryō Kofun is one of the largest mounds in the Mozu cluster and is about 365 meters long. It is extremely well-preserved.
Ishibutai Kofun, located in Asuka, is linked to Soga no Umako. Ishibutai Kofun contains some of the largest megalithic stones used in any Japanese burial monument. It is special because visitors can walk inside a kofun.
Konabe Kofun is in the center of a large moat. As one of the best-preserved keyhole tombs, it is a fine example of elite burial architecture from the middle Kofun Period.
Sakurai Chausuyama Kofun is one of the earliest giant royal tombs and helps to show early Yamato political power. It contained important grave goods such as bronze mirrors.

Sengenzuka Tomb, Itako, Ibaraki. (Koishikawa Hitomi/CC BY-SA 4.0)

These kofun show Japan’s growing power in the fourth and fifth centuries. Some strong rulers could assemble thousands of workers to build the tombs. Skilled planners, builders, and craftsmen designed and constructed these monumental tombs. The rulers used a trade network to obtain supplies, and there is evidence for cultural exchange involving technology, metallurgy, political institutions, and later religious ideas from the Korean Peninsula and China. The size and design of these kofun lead some researchers to compare them to Egypt’s pyramids and the royal tombs of ancient China, symbolizing state formation and elite power

Terracotta figures are some of the grave goods placed around the tombs. (Gary Todd/PD-CC0 1.0)

Burial Rites and Grave Goods

The tombs reflect indigenous beliefs concerning ancestors, sacred landscapes, and spiritual forces later associated with Shinto traditions. The presence of rich grave goods suggests beliefs concerning the status and continued significance of the deceased after death. The tombs contained mirrors, jewelry, armor, weapons, and ceremonial objects. UNESCO views the tombs as one way that early societies demonstrated the power of the ruling class. Many kofun designated as ryōbo (imperial mausolea) are administered by Japan's Imperial Household Agency, which restricts archaeological investigation of these sites. Japan’s Imperial Household Agency manages these tombs to maintain their authenticity since they are close to urban development.

The Kofun Period Was an Influential Era of Transition

Before the Kofun Period, the residents of the Japanese archipelago were farmers living in small villages. They grew rice, made crafts, and produced woven cloth. Rice agriculture formed the basis of many communities, supplemented by fishing, hunting, and gathering. Their communities were united by allegiance to clans and local leaders. The leaders had associations with regional rulers. Their lives changed during the Kofun Period when the islands transitioned from chiefdoms to a centralized political system and imperial traditions. Leaders made alliances with regional chiefs.

The Kofun Period represents the transition from scattered chiefdoms to a centralized political system. The noble families, known as uji, claimed divine ancestry. The Yamato rulers supported the use of horses, invested in iron technology, and valued writing. Leaders also emphasized military power that used an elite warrior class. Archaeological excavations have uncovered military artifacts such as armor and helmets, iron swords, spears, and horse saddles. Horses were introduced to Japan through interactions with societies on the Korean Peninsula during the fourth and fifth centuries. Warriors rode horses into battle, and they represented the king’s status and military power. Horses likely improved communication, transportation, and military mobility across expanding political networks.

The Kofun Period Marks One of the Foundational stages in the Formation of the Japanese State

The Kofun Period was a transformative era. The immense kofun mounds are symbols of a society capable of assembling resources and labor before the establishment of a central imperial government. The tombs offer a glimpse into a world of evolving social hierarchies, expanding trade networks, and growing connections with the Korean Peninsula and China. The period witnessed the development of new technologies, military practices, and religious traditions that gradually transformed the Japanese archipelago. The kofun tell the story of a society in transition between prehistoric Japan and the imperial state. The Kofun Period created the foundation for the culture and traditions of modern Japan.

Top image: Forested Kofun burial mound surrounded by a moat. Source: Saigen Jiro/CC0 1.0

By Ramsey Hardin