NHK has learned that Japanese archaeologists excavating a site in central Turkey have found heated iron ore from a stratum dating to the Bronze Age, about 4,200 years ago.

The findings could offer clues to how ironmaking began.

The team led by Omura Sachihiro of the Japanese Institute of Anatolian Archaeology, an affiliate of the Middle Eastern Culture Center in Japan, has been studying the Kaman-Kalehoyuk ruins for 40 years.

Team members used an electron microscope to analyze pieces of metal, measuring several centimeters across, that were unearthed from about 4,200-year-old stratum at the northern side of the ruins.

Two of the pieces were found to have been made from heated iron ore, and another was identified as artificial iron.

It is said that ironmaking thrived across the Hittite Empire about 3,400 years ago.

But the team's findings suggest people in the Bronze Age, before the Iron Age, were already trying to make iron using copper smelting techniques.

The team also unearthed remains of about 10 furnaces from the same stratum, and plans to examine whether they were used for ironmaking.

Omura said attempts to make iron likely began nearly 1,000 years before the Hittites by applying techniques for producing copper and bronze.

The team will report on the excavation at the Tokyo National Museum on March 9.