From the perspective of those on the ground, one of the world’s largest graves appears to be an expansive, natural respite nestled in the bustling urban core of Japan’s Sakai City. When viewed from above, however, the massive forest becomes a green keyhole surrounded by three moats in the shape of a doorway.
This is Japan’s Daisen Kofun, an ancient burial mound shrouded in mystery, massive in scale, and surprisingly little-known to the rest of the world.
Much like the ancient Egyptians built pyramids to honor deceased royalty, the Japanese interred their emperors and other notable figures in megalithic structures known as kofun or tumuli. Between the early 3rd century and the early 7th century A.D., during Japan’s Kofun period, an estimated 200,000 keyhole-shaped tombs were constructed throughout the Japanese archipelago.
The Daisen Kofun, believed to be at least 1,600 years old, is the biggest tumulus and one of the three largest tombs in the world, sharing court with both the mausoleum of the First Qin Emperor in China and the Great Pyramid of Khufu in Egypt.
While the entire moat-ringed complex spans 110 acres, the tumulus itself measures an impressive 1,600 feet long by 980 feet wide. It is part of a cluster of smaller tumuli, called the “Mozu kofungun,” which are currently under consideration for inclusion on the UNESCO World Heritage List.
In fact, since the late 19th century, the Daisen Kofun has been expressly off-limits to tourists, archaeologists and even royalty. Reportedly, no one has crossed the inner-moat and visited the island since 1872, when a typhoon damaged the lower part of the keyhole shape. The Imperial Household Agency, which manages the Daisen Kofun and others like it throughout Japan, has prohibited human contact on the grounds that “tranquility and dignity” should be maintained at the sacred site.
As such, the agency has been content to let the tomb revert to a natural state, with the grounds covered in a thick forest of native trees and the surrounding moats providing sanctuary for fish and waterbirds. Today, tourists interested in viewing the site can do so only from either a platform across the second moat or by walking the nearly-two mile path around the tomb’s outer dike.
Based on other keyhole mounds excavated around Japan, the upper circular part of the structure is where the bodies were entombed, while the lower rectangular area was used for mortuary rites. A 1995 article in the Independent reported that there may be as many as “26,000 tons of stone slabs” buried beneath the kofun, with “swords, jewels, crowns, statues, and the coffined remains of the great god- emperor himself” sealed inside.
Of course, as far as anyone knows, no one has explored the circular region of the tumulus in more than 16 centuries. The biggest question of whether or not the treasures of the emperor lie undisturbed remains unanswered.