1st-3rd century mining tunnel in Tokushima Pref. could be oldest in Japan

ANAN, Tokushima -- Researchers have dated a mining tunnel here to the late Yayoi period in the first to third centuries, making it the oldest mine gallery in Japan by at least 500 years.

The Anan Municipal Government and the Tokushima Prefectural Board of Education held a news conference at the city office to announce the findings on March 1.

"(The discovery) proves that Yayoi people, whom we tend to see as very agricultural, had techniques sufficiently advanced to excavate things like tunnels," commented Tetsuya Okubo, a professor of archaeology at Tokushima Bunri University.

Previously, it was believed that Japan's oldest mining tunnel was at the Naganobori Copper Mine Site in Yamaguchi Prefecture in the west of the country, dug in the early Nara period in the eighth century.

In Anan, also in western Japan, stone tools for refining cinnabar -- used as red pigment -- have been discovered at the city's Wakasugiyama Site, and mining activities confirmed from the third to the seventh centuries, from late Yayoi to the beginning of the Kofun period. However, it was believed that Yayoi miners only dug surface pits, as they lacked advanced techniques to drill into hard rock and carve out mine galleries.

In 2017, a tunnel thought to be a mine gallery was found on a local hillside, and the city conducted an excavation in fiscal 2018. The tunnel turned out to be 0.7 to 1.2 meters high, 3 meters wide and extended 12.7 meters into the hillside. More than 10 fragments of earthenware were discovered about 3 meters from the entrance and, based on the implements' style, the excavation team judged that five of them had been made in or around the late Yayoi period.

Refined cinnabar had high scarcity value, as it was used to paint stone chambers and coffins for mourning the dead, according to the team.

(Japanese original by Kazuya Osaka, Tokushima Bureau)