A tumulus in Wadayama, Hyogo Prefecture, has turned out to be one of the largest burial mounds in the Kinki region and contains numerous artifacts, the prefecture's board of education said Wednesday.

The tumulus, created in the early part of the 5th century, has a diameter of about 86 meters. Some 200 iron items, including swords and helmets, and numerous accessories have been found.

According to the board, which oversaw the excavation, the tumulus is the first undisturbed circular mound found in Japan with a diameter greater than 80 meters.

The number of iron items discovered equals that found in burial mounds of officials who ranked just below the kings during the Yamato Era (300-710), the board said.

"The tomb probably belonged to an influential warrior who ruled the Tajima area, a busy junction with much traffic, and who had close links with the Yamato regime," a board official said.

The tumulus, named Chasuriyama, was found in 1992 during a land survey conducted as part of planned expressway construction.