Photo/IllutrationThe pits in the ground suggest the ancient structure in Asuka, Nara Prefecture, measured at least 19.2 meters west to east. (Yoshinori Mizuno)

ASUKA, Nara Prefecture--Researchers found evidence of an oblong structure from the Asuka Period (592-710) that was likely part of a banquet hall complex for the nobility described in an eighth century official history of Japan.

The building dates from when Asuka served as the nation's capital, and its existence was announced by the education board of the Asuka village government on Feb. 21.

Researchers uncovered pits in the ground for 16 wooden pillars in the Asukadera Seiho site, which lies west of the old Asukadera temple. The pits were uncovered in the northwest part of the archaeological site and are believed to date from the seventh century.

The pits measure between 90 centimeters and 135 cm across. The placement of the pillars suggests the banquet hall measured at least 19.2 meters west to east and 4.8 meters south to north.

The old Asukadera temple is thought to have been the first Buddhist temple founded in Japan. The area west of the temple is considered to be the site of “Tsukinoki no Hiroba,” or famed square of zelkova trees mentioned in “Nihon Shoki” (The Chronicles of Japan), completed in the eighth century.

The book describes banquets held in the square in the latter half of the seventh century for people invited from the outskirts of the kingdom, including the Emishi from today’s Tohoku region and the Hayato from the southern Kyushu region.

Kanekatsu Inokuma, professor emeritus of archeology at Kyoto Tachibana University, believes “the square was a functional venue for various rituals,” adding that the discovery ties in with historical accounts of banquets hosted for the Emishi and Hayato people, with sumo tournaments put on for entertainment.

"Just how they are described in Nihon Shoki,” he said.

Tsukinoki no Hiroba is reputed to be where the young Emperor Tenji as crown prince first became acquainted with Nakatomi no Kamatari through a “kemari” ball-kicking game. They connived to stage a coup in 645 that brought about the Taika Reforms to cement the power of the imperial court.

About 300 meters north of the Asukadera Seiho site lie the Ishigami archaeological ruins, which yielded a stone figure, probably a fountain.

The Ishigami site bears traces of a facility that was enclosed by a narrow corridor-like building, which is believed to have been part of a much larger banquet complex.