Daisenryō Kofun and other tombs are clearly visible in the Sakai urban area on satellite images
Photo: Sentinel Hub / ESA
When it came to burying important personalities, our ancestors sometimes went to a lot of trouble.
For example with the pyramids of Giza near Cairo, which are probably among the most impressive structures of mankind.
Owning a tombstone almost 140 meters high, like that of Pharaoh Cheops, to whom the largest of the pyramids was dedicated, is special.
The Taj Mahal in India is also a superlative mausoleum that fascinates visitors to this day.
Burial mounds from different cultures also reach considerable sizes.
The Scythian kurgans can be seen from afar across the Eurasian steppes.
Inside, archaeologists found magnificent gold work.
Very special, sometimes gigantic burial mounds are known from Japan, here they are called Kofune.
There are tens of thousands of such sites across the island nation, but the Daisenryō Kofun found fame near the shores of Osaka Bay.
It is one of the largest monuments ever erected on earth: 486 meters long and 36 meters high, surrounded by three moats.
It is said that it took 2,000 men toil for 16 years to build for Nintoku, the sixteenth Emperor of Japan.
No other kofun reaches this size and not all are perfectly round.
Especially the larger systems often have the shape of a keyhole.
A Japanese peculiarity that basically only becomes clear when you look at it from the air – just like in the satellite image above.
Science also needs this perspective for the burial sites that were laid out between the third and seventh centuries AD. Because archaeologists cannot simply dig up the facilities. Access to the central areas is prohibited, they are still considered sacred, religious sites. Many monuments are fenced off and it is not allowed to enter them. For these reasons, it is impossible for researchers to make accurate measurements of size, height, and orientation.
Scientists from Italy have therefore now evaluated high-resolution satellite images to find out more about the mysterious burial mounds.
She was particularly interested in the arrangement.
The result of the study by Norma Baratta, Arianna Picotti and Giulio Magli from the Politecnico di Milano, now published in the specialist magazine »Remote Sensing«, shows: The hundred or so hills that were evaluated for the study are laid out according to a specific pattern.
The entrance areas leading to the interior of the underground facilities and to the stone burial chamber are all aligned with the arc of the rising sun.
This fits well with what is known about Japan's early imperial tradition.
In mythology, the rulers saw themselves as the direct descendants of the sun goddess Amaterasu.
In the case of the key-shaped Kofunen, the burial chambers are usually located in the round part of the mound. The shape of these enclosures was not chosen by chance: only priests and ministers had access to this round part of the keyhole during the burial ceremony. It was here that the successor to the late Tenno was decided. Family members, on the other hand, were only allowed to attend the procession of coffins on the wedge-shaped part of the complex.
The Daisenryō Kofun is also very clearly aligned with the sun, the researchers write.
Apparently, people oriented themselves here by the sunrise at the winter solstice.
However, little is known about the interior of the hill, which was only recently inscribed on the Unesco World Heritage List.
In 1872 a heavy storm hit the giant tomb.
At that time, helmets, glass bowls and clay figures appeared.
But unless such damage occurs, the keyhole to the underworld remains locked.
Then nobody is allowed to go beyond the bridge of the second moat.