Senshu’s UNESCO World Heritage site,

the Mozu-Furuichi Kofungun, are thought to be the resting place of emperors.

Osaka & Senshu’s First World Heritage Site – Mozu-Furuichi Kofun Group

Senshu is home to the Mozu-Furuichi Kofun Group, mounded tombs of ancient Japan which have a distinct keyhole shape when viewed from above. It is believed that high-ranking individuals such as princes and emperors are buried in these mounds—the largest is believed to be the burial site for Emperor Nintoku. It was registered as a UNESCO World Heritage Site in 2019 in recognition of its historical and societal significance.

An Ancient History

The Mausoleum of Emperor Nintoku.

The Kofun period (approx. mid-3rd century-late 6th century) saw the rapid development of the ancient burial mounds (kofun) which is believed to have evolved from the Yayoi period (300 BCE–300 CE), where burial in designated areas where terrain was elevated became custom. It is believed that kofun-style burial mounds, with raised ground and a keyhole shape, became common in the 3rd century. It has also been suggested that certain characteristics are prevalent in preexisting tombs found on the Korean peninsula. The earliest recorded history of the imperial family of Japan is believed to date back to the 8th century.


The history surrounding kofun during the period between the 3rd and 6th century is unknown, but it is believed that rulers called okimi, an honorific title given to princes and princesses, were buried in enormous kofun during this time. It is suggested that okimi shared a connection with the establishment of Japan’s imperial family.

Scenery around the Mausoleum of Emperor Hanzei (336-410).

To obtain scientific evidence, it is vital to excavate the kofun to collect data. Since excavation will almost certainly destroy the kofun, careful advanced planning is required. Any relics excavated run the risk of rusting rapidly when exposed to air. Preservation of kofun is also paramount; there were over 100 in existence throughout the Sakai City, but now there are only 44 left. The others disappeared because of excavations, reclamation of land for development, and general damage.

The Kofun Structure

Replicas of relics from the Jomon Period offer insight into their way of life. (Photo taken September, 2020)

Each kofun is characterized by the iconic keyhole shape, and is typically surrounded by a moat. These characteristics are thought to be unique to Japan, especially when compared to burial mounds of a similar size from the same period found throughout the globe. The pyramids of Egypt, for example, have square bases that lead to a point, and European tombs are typically round, both quite common shapes compared to that of the kofun. The grave mounds also do not have an associated moat.


The locations of kofun were also carefully selected to be on elevated ground. This is to ensure that they are visible from a distance. Three-tiered mounds were created and the slopes are clad in stone to prevent soil from collapsing. A red, fence-like structure was lined up on each layer. Household items and personal belongings of the buried individual were also placed on the kofun. The round part at the top of the keyhole shape is where the individual was buried. The deceased was placed in a stone coffin, and more personal artifacts were placed in and around the coffin.


To construct the kofun as many as 2,000 people were involved on a daily basis. It possibly took up to 16 years to complete construction, and the contribution of some 6.8 million laborers. The size of the tomb is thought to reflect the power and influence of the individual who is buried, which makes these mounds quite impressive indeed.

Nintoku-san: The Largest Kofun in Sakai

A birds-eye view of the Mozu Tombs.

It is believed that the largest kofun burial mound in Sakai City is the burial site for Emperor Nintoku (Daisen Kofun). It measures 307 meters in width and 486 meters in length. The highest point of elevation, the rounded part where the coffin would have been buried, is 35.8 meters tall.


Emperor Nintoku was the 16th emperor of Japan, and ruled during the 4th century. Local residents have affectionately nicknamed the burial site “Nintoku-san,” which is a play on words; the honorific -san is a polite ending to someone’s name, but is also affixed to the names of mountains. Many volunteer groups regularly clean the site around the kofun, and officials regularly enter the mound to carry out maintenance work.

Sakai City Museum

The façade of the Sakai City Museum.

To learn more about the history surrounding kofun and to see some of the excavated artifacts, visit the Sakai City Museum, which is located in Daisen Park just opposite the Daisen Kofun. The museum is open daily from 9:30 a.m. to 4:30 p.m., and is closed on Mondays. The permanent exhibition is available to view year round, and they regularly host special exhibitions.


Popular souvenir items showing the iconic keyhole motif are available for purchase at the museum and in nearby stores.


*Please note that a portion of the exhibition area will be closed for construction, and is scheduled to reopen on March 12, 2021.


For Senshu tourist information inquiries, please contact the Senshu Japan Concierge Team.


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