24-04-2025
Experts identify the species of Shosoin's famed 'dragon' mummy
The "Koryu" mummy (Captured from No. 47 Bulletin of Office of the Shosoin Treasure House)
NARA—The species resembling a "dragon" mummy that has long been kept in the Shosoin Repository here, a World Heritage site, has been positively identified through X-rays, it was announced on April 23.
Zoologists and other experts have determined that the mummified body was an adult female Japanese marten from the weasel family, according to the Shosoin Repository office of the Imperial Household Agency.
The mummy, called "Koryu," was among the treasures kept at the repository.
The experts closely examined objects made from animal horns and bones, as well as fossils that had been kept as medicinal ingredients from centuries ago, and identified their species.
Along with the Koryu, some treasures that were thought to be ivory and reindeer antlers, respectively, have been found to be parts of different animals.
On April 23, the Imperial Household Agency's Shosoin office based in Nara announced the results of appraisals by zoologists and archaeologists from the National Museum of Nature and Science and the University Museum of the University of Tokyo.
The Koryu is a mummified animal resembling a small dragon that was thought to be a mammal, measuring about 40 centimeters in length from head to part of the tail.
In an investigation in the 1950s, it was tentatively identified as a marten based on the shape of its teeth that can be observed from the outside. Fragments of several other types of mummies have also been handed down as parts of other so-called Koryu.
X-RAY EXAMINATION
When did the Shosoin Repository begin keeping the Koryu mummy?
The Koryu doesn't appear in documents handed down from the Nara Period (710-784).
When the sixth shogun of the Muromachi Shogunate Ashikaga Yoshinori (1394-1441) visited Todaiji temple in 1429, he cut off a part of Ranjatai agarwood that had been passed down in the repository.
A monk at Todaiji temple wrote in his diary that at the time, the shogun found an object resembling a dragon, which was dried by sunlight. So, the Koryu mummy is believed to exist from around the time.
This time, the mummy of the marten was confirmed by a more comprehensive observation of the teeth and head bones through X-rays.
In addition, radiocarbon dating was used for the first time of a Shosoin Repository treasure, and it was determined that it dates from the mid-11th century to the mid-12th century.
Furthermore, it was found that the fragments from other Koryu kept by the repository included a mole's front legs, a crow's legs and a pigeon's hip bone.
The research group concluded that, considering the records of five repairs to the repository in the 11th and 12th centuries and that there are still gaps in the ceiling of the repository, it is believed that a marten invaded the repository and died and became a mummified animal inside the treasure house.
However, the research group also concluded that it is possible that the Koryu mummy was brought there on purpose, considering that the front legs have not been found in investigations of the treasure fragments that have been ongoing since the Taisho Era (1912-1926).
Records from the Muromachi Period (1336-1573) reported that it would rain whenever the repository was opened due to the presence of the dragon-looking mummy.
For the recent investigation, it rained heavily on the scheduled date when researchers would come from Tokyo to prepare for specifying the dates, and Shinkansen services were suspended. So, the plan was postponed.
It is also believed that people started to call the mummy Koryu around the Edo Period (1603-1867).
"The age determination research this time has significantly increased the possibility that the mummy is the same as the sun-dried dragon-looking object recorded in the document from the Muromachi Period," Mami Tsuru, a member of the conservation science department at the Shosoin office, said at a news conference on April 23. "We believe this is a good example of how Shosoin has protected not only beautiful items, but also all the items inside the repository."
ANALYZING FOSSILS
Experts have also analyzed other animal fossils that had been kept in the repository as medicinal ingredients.
The distinctive elephant molar teeth were determined to be those of an Namadicus elephant, an extinct species close to the Naumann's elephant, which also lived in the Japanese archipelago. The Namadicus elephant inhabited from China to India.
Other items examined included deer antlers, which were not confirmed to exist in the Japanese archipelago, and hyena teeth.
Most treasured items, such as a ruler and a scepter, which have been said to be made of ivory, and a cup believed to be made from a rhinoceros horn, were confirmed to be made from the materials that have been documented in history.
Meanwhile, the curved animal bones that had been passed down as "ivory" were found to be whale ribs. In addition, ramified horns that had been thought to be reindeer antlers were found to be from a species of deer called the Pere David's deer, which inhabits China.
The research report was published in the 47th issue of the Bulletin of Office of the Shosoin Treasure House. It can be downloaded for free from the Shosoin office website (
