Nintoku Tennei Ryo Kofun

The Daisen Kofun, or Emperor Nintoku's tomb, located in Daisencho, Sakai City, Osaka Prefecture, is the largest keyhole-shaped burial mound in Japan. It spans approximately 486 meters in total length, with a diameter of about 249 meters and a height of approximately 35.8 meters at the circular rear section, and about 307 meters wide and 33.9 meters high at the square front section, showcasing its overwhelming scale. The mound is built in three tiers, with protruding structures called "zōdashi" at the constricted points on both sides, surrounded by three layers of moats. The current outer moat was excavated during the Meiji period.

This burial mound is noted in the Heian period "Engishiki" as "Mozu no Mihara no Naka no Misasagi" and is presently designated and managed as the tomb of the 16th Emperor Nintoku by the Imperial Household Agency. It, along with the Funajo Kofun (Takedaizan Kofun) to the north and the Richū Kofun (Mizanzai Kofun) to the south, is collectively referred to as the "Mozu no Mihara Three Mounds."

The mound is adorned with surface stones, and many haniwa (terracotta clay figures) were arranged around it. Among the unearthed haniwa, a variety of shapes can be seen, including human figures (female heads), waterfowl, horses, deer, and house shapes. Research conducted in the 1950s and recent years has uncovered Sue pottery jars from the protruding structures, which are considered valuable materials for determining the period of construction.

In Meiji 5 (1872), a vertical hole stone chamber believed to be part of the front part was exposed, revealing a long-shaped stone coffin, swords, armor, glass jars, and dishes among the artifacts. These burial goods were reportedly reburied, but detailed records from that time remain, indicating that the armor was made of luxurious gold and copper. The Boston Museum of Fine Arts in the United States is said to house items believed to have been excavated from this tomb, such as a "fine-lined beast-pattern mirror" and a "single phoenix-tipped sword," although the provenance of these items is not confirmed.

Additionally, over ten small burial mounds known as "baichō" have been identified surrounding the main tomb, further enhancing the grandeur of the Daisen Kofun. Recent studies suggest that these smaller mounds were built after the Richū Kofun, indicating a discrepancy from the order of reign recorded in the Nihon Shoki.

Currently, a pathway of about 2.8 kilometers has been established around the site, allowing visitors to walk around this majestic burial mound in about an hour. Alongside the Great Pyramid of Giza in Egypt and the Mausoleum of the First Qin Emperor in China, the Daisen Kofun is considered one of the "Three Great Tombs of the World," making it an extremely important archaeological site that symbolizes ancient Japanese history.