Timber of Jomon period processed to make mortise-tenon joint discovered

A tiber with a tenon discovered at the Mawaki remains of the Jomon period Photo: The Yomiuri Shimbun

The Yomiuri Shimbun, 30 Jan 2015
KANAZAWA — A rectangular timber with its tip shaped into a tenon, presumably from the Jomon period, has been discovered among ancient ruins in Noto, Ishikawa Prefecture, according to the town’s board of education.

The timber, discovered at the town’s Mawaki remains from the Jomon period (ca 10,000 B.C. to 300 B.C.), is believed to be the oldest of its kind ever found in Japan, according to the education board.

Until today, the mortise-tenon joint technique is believed to have started in the Yayoi period (ca 300 B.C. to A.D. 300), as no timbers with a tenon were discovered from any timber remains before the Yayoi period.

The mortise-tenon technique is a method used to join two pieces of timber. According to the announcement, the discovered timber, about 1 meter long, had a 10-centimeter-long tenon that is 6 centimeters thick.

The timber is 16 centimeters wide at its widest area and about 7 centimeters thick. The tenon and the joint part were elaborately whittled so the timber could be connected vertically. The shape of the tenon was close to that of a contemporary tenon, according to observers. No timber pieces with a corresponding mortise have been found.

“It is an important historical discovery in terms of studying woodwork from the Jomon period,” said Tokyo Metropolitan University Prof. Masahisa Yamada, an expert on archaeology who participated in the excavation. “It is possible the timber was made as part of a column for a special facility for a ritual of some sort, not for a house.”

According to Yamada, timbers were excavated from the Jomon-period Miyanomae remains in Hida, Gifu Prefecture, but they were not processed to make a mortise-tenon joint.

Primitive tenons had been disocvered in two ruins of the Jomon period — the Oshorodoba remains in Otaru, Hokkaido, and the Shimoyakabe remains in Higashi-Murayama, Tokyo. However, they were logs, and their tenons had been made simply by shaving the edge of the log.