http://www.archaeology.org/news/4658-160719-japan-korean-style-tools-discovered

  EBINO, JAPAN—According to the Asahi Shimbun,archaeologists excavating a sixth-century A.D. tomb on the island of Kyushu have discovered iron blacksmith tools decorated with silver inlay, which strongly suggests they were influenced by Korean styles of the time. The artifacts, which appear to be a chisel and and a pair of bow tongs, were X-rayed and discovered to have waving inlaid silver patterns similar to those found on Korean swords that date to the same period. "It is totally unheard of to find metal inlaid works on items other than long swords and horse harnesses from around that time,” says Kagoshima University Museum archaeologist Tatsuya Hashimoto. Scholars note that the technique may have been introduced to Japan by Korean migrants, and that the tomb's occupant was likely an important personage who was possibly responsible for craftsmen in the area.

Apparently, Japanese scholars and archaeologists are shocked at highly advanced iron tools found from one of the suspected ancient Korean kofun from Ebino, Kyushu island. Japanese media tried to paint these artefacts was Korean styled blacksmith tools, a chisel and tongs ... which is essential for blacksmithing iron and other metals. They are extensively used along with hammer to bash & flatten iron and bronze. So we know where Japanese got their sword smiting from as well. These weren't just Korean styled tools, but tools from ancient Korea. These same tools are found all over Korea. Looks like many Kofun owners were indeed Korean descent in Japan. 

Researchers said the metal inlay in a wave pattern is commonly found on long swords made in the Korean Peninsula between the fifth and sixth centuries. They said the technique was likely passed down around the mid-fifth century from Korean migrants who introduced many technologies to Japan in ancient times.

Among the many burial accessories found in the tomb were items believed to have been gifted from the ancient Yamato kingdom, as well as artifacts made in the Korean Peninsula.

“It is totally unheard-of to find metal inlaid works on items other than long swords and horse harnesses from around that time,” said Tatsuya Hashimoto, an associate professor of archaeology at Kagoshima University Museum, also in Kyushu, who analyzed the X-ray images of the tools.

“There is a possibility the occupant (of the tomb) was in charge of the craftsmen and industries in the area,” he added. “He may well have been a soldier deployed to the Korean Peninsula as part of reinforcement efforts.”

Toshio Tsukamoto of the Gangoji Istitute speculated that the occupant of the tomb was of Korean descent.

Tsukamoto said the man was likely “a highly skilled craftsman who was honored in death for his contributions to the metal industries.”

Hidemasa Hashimoto, an associate professor of archeology at Tenri University in Nara Prefecture, said, “We never expected to see inlay work on a craftsman’s tools, and the discovery will spur a lot of debate among us. Through further study, I believe the items will reveal where they were made and how they ended up there.”

http://www.asahi.com/ajw/articles/AJ201607190074.html