An iron artifact unearthed at an archaeological site in Fukui Prefecture may be part of a saw dating back to the late Yayoi period (second to third centuries), potentially making it the oldest known example of its kind in Japan, researchers have announced.

The object was discovered at the Hayashi-Fujishima archaeological site. Measuring 4.1 centimeters in length, up to 2.1 centimeters in width, and approximately 1 millimeter in thickness, the artifact features triangular teeth ranging from 1 to 3 millimeters in depth.

The discovery was detailed in an academic bulletin published by the Fukui Prefectural Archaeological Research Center, which led the investigation.

“The artifact could provide important evidence of the development of ironworking culture along the Sea of Japan coast during the Yayoi period,” said Tomokatsu Uozu, deputy director of the research center.

Similar saws dating to the second and third centuries have previously been found in China. Researchers believe iron-processing technologies likely spread from the Chinese mainland through the Korean Peninsula to northern Kyushu before reaching Fukui via trade and cultural routes along the Sea of Japan.

The Hayashi-Fujishima site covers roughly 1.5 kilometers from east to west and about 2 kilometers from north to south. Excavations conducted between 1996 and 2003 uncovered a wide range of artifacts, including pottery, stone tools, and iron implements.

Archaeologists also identified the remains of a late Yayoi settlement that contained a workshop for producing ornamental beads, such as comma-shaped magatama and tubular kudatama.

The saw-like features were discovered during conservation and restoration work on excavated artifacts carried out in fiscal 2021. Researchers identified serrations resembling saw teeth on the iron object and subsequently analyzed it using X-ray CT scanning.

The scans suggested that the artifact may have been part of a “beak-shaped” iron saw with a pointed tip. Based on the surviving fragment, researchers estimate the original tool was between 15 and 20 centimeters long before it broke.

The bent tip, angled at roughly 60 degrees, indicates the saw may have been used for detailed work on wooden objects or stone materials.

The research center plans to continue examining the artifact.

Until now, the oldest iron saw discovered in Japan was believed to be a specimen from the early Kofun period (late third century) excavated from a burial mound in Tatsuno, Hyogo Prefecture.

If the Hayashi-Fujishima artifact is conclusively identified as a Yayoi-period saw, it could push back the known history of saw use in Japan by 50 to 100 years—or possibly even longer.