Archaeologists on Wednesday said they have excavated a site that contains the possible foundations of an eighth century Parliament building in the town of Shigaraki in the prefecture.
The foundations suggest the building measured about 92 meters by 12 meters, according to researchers from the Shigaraki municipal education board.
The foundations were discovered on a site believed to be where the Shigaraki-no-miya Palace once stood in a town that Emperor Shomu (701-756) used as the country's capital for about five months in 745.
Other ruins believed to have been part of the Emperor's residence had previously been uncovered at the site, the researchers said.
Statesmen and officials are believed to have discussed politics on behalf of the Emperor in this type of Parliament building, called "chodo," they said.
The scale of the building appears to be similar to that of one unearthed earlier at the ancient capital of Heijo, currently the city of Nara. The structure is unique, however, because it seems to have had eaves on the north side as well as the east and west, according to researchers.
The remains of what appears to have been main thoroughfares as well as the ruins of some bridges that ran along them were also discovered, presenting the strongest evidence to date that the site is indeed that of the Shigaraki-no-miya Palace, they added.
The ruins of what appears to have been a road that was as much as 12 meters wide were also found, with a nearby tree trunk confirmed by researchers to have been from a tree cut down around 744.
Up to now, a site roughly 2 km to the south had been believed to be the site of the former capital.