YOSHINO, Nara Prefecture--Building a palace near the water’s edge isn’t the safest location, as it could endanger the lives of its residents in the event of flooding and other natural disasters.

However, a mysterious ancient palace was likely situated just beside the beautiful Yoshinogawa river during the Nara Period (710-784), possibly for the waterfront view afforded, according to new findings.

Ruins of a large building dating to the first half of the eighth century have recently been unearthed only 20 meters from the Yoshinogawa, which winds its way between mountains in southern Nara Prefecture.

The structure discovered at the Miyataki archaeological site here boasts special designs unique to emperors’ palaces, increasing the possibility that the find was the main building of the Yoshino no Miya detached palace, which records say Shomu (701-756) and other emperors frequented.

Archaeologists are currently making eager efforts to unlock the mystery of why the detached palace was built so close to the river.

Researchers of ancient history and the "Manyoshu" (Collection of Ten Thousand Leaves) poetry anthology have had aggressive discussions to identify the location of Yoshino no Miya since before World War II.

As the ruins of many buildings have been discovered in the Miyataki archaeological site along the Yoshinogawa in recent excavation surveys, Miyataki is deemed as an area where Yoshino no Miya was highly likely located.

But it was unclear where the central part of Yoshino no Miya was. Most experts estimated the “residence where the emperor stayed must be on the safer mountain side, from which magnificent views can be enjoyed.”

However, the ruins of a building whose intercolumniation measures 16.3 meters east to west and 9 meters north to south were unearthed at Miyataki in an excavation that was started in December last year by the Yoshino education board and the Archaeological Institute of Kashihara, Nara Prefecture.

While the huge building is believed to have had eaves on all its four sides, such an architecture was only allowed to be constructed for use as the Daigokuden hall, where the emperor administered political affairs, and the main building of the Dairi private residence of the emperor.

Michio Maezono, an archaeology professor at the Nara College of Arts, explained why the main structure of Yoshino no Miya was set up near Yoshinogawa based on the fact that various religious rites were held there since the Asuka Period (592-710).

“Core buildings were possibly installed near the river as religious services were held to honor the god of Yoshinogawa,” Maezono said.

Makoto Ueno, a professor of Manyoshu studies at Nara University, said Manyoshu poet Yamabe no Akahito, who is said to have lived around the same period as Emperor Shomu, described Yoshino no Miya as “land by a clean river” in his work.

“I previously thought the poem depicts the palace in an exaggerated way, but (the latest discovery of a large building near the river indicates) Yoshino no Miya was likely a detached palace to enjoy the beauty of the Yoshinogawa just as depicted in the poetry,” said Ueno.

According to “Nihon Shoki” (The Chronicles of Japan), Yoshino no Miya was commissioned in 656 during the Asuka Period by Emperor Saimei (594-661). Empress Jito, who reigned between 690 and 697 after succeeding her husband, Emperor Tenmu (unknown- 686), visited there on 31 occasions.

“Shoku Nihongi” (Chronicles of Japan, continued), Japan’s official book of history of the Nara Period, and other sources state the Yoshino no Gen administrative office was introduced to manage Yoshino no Miya during the period and given a special status.

While Shomu visited Yoshino no Miya soon after ascending to the throne in 724, he also went there in 736.

A "mokkan" wooden tablet associated with Shomu’s second visit to Yoshino no Miya has been discovered from a hole near the Heijo Imperial Palace in Nara city. Powerful aristocrat Fujiwara no Maro (695-737) is said to have helped send food and tableware to Yoshino no Miya and arranged personnel to accompany the emperor.

Akihiro Watanabe, deputy director-general of the Nara National Research Institute for Cultural Properties, who studies Japan’s ancient history and is familiar with mokkan, said the discovered wooden strip reveals how important the visit to Yoshino no Miya was.

“The mokkan clearly showed thorough preparations were made for the Yoshino trip,” he said. “The recently discovered building is highly likely part of Yoshino no Miya depicted in the mokkan, considering its building period and other characteristics.”

Watanabe also touched on the possible reason why the building was set up there.

“Putting priority on viewing magnificent views up close, it (the palace) was likely constructed by the river,” said Watanabe.