Two glass beads that bear the characteristics of Roman craftsmanship have been found in a 5th century tomb in Nagaoka, near Kyoto in southern Japan.
The tiny five-millimeter (0.2 inch) beads date to between the 1st and the 4th century A.D. and were made with natron, a naturally occurring chemical that was widely used in ancient Egypt for everything from brushing teeth to mummification. The Romans added it to sand and lime to make ceramics and glass. The process fell out of use in the 7th century A.D.
The beads, which have a hole through the middle, were made with a multilayering technique — a relatively sophisticated method in which craftsmen piled up layers of glass, often sandwiching gold leaf in between.
“They are one of the oldest multilayered glass products found in Japan, and very rare accessories that were believed to be made in the Roman Empire and sent to Japan,” said Tomomi Tamura, a researcher at the [Nara National Research Institute for Cultural Properties].
The “sent to Japan” part is questionable (a translation issue, perhaps?). There was no direct trade between Rome and Japan. As early as the 1st century A.D., the complex of trading networks on sea and land that are known today as the Silk Road ran from Europe through Africa, Arabia, Persia, India, China, and Korea to Japan and back again. Traders did local legs of the massive voyage, stopping at market cities to sell their goods which would then be traded again a little further away and so on, until silk from China wound up adorning Roman emperors and Roman gold-flecked glassware jewels ended up the prized possession of a 5th century Japanese nobleman.
We don’t know when the beads got to Japan. They could have been recent purchases, or heirlooms handed down from parent to child for centuries before their burial, or they could have come to Japan along with the many Chinese and Korean immigrants who became naturalized Japanese and held important positions at the Yamato court during the Kofun period (250-538 A.D.). (Kofun, incidentally, is the word for the burial mounds of royalty and aristocracy that characterize the period, like the one in which the Roman jewels were found.)
It’s also eminently possible that they made it to 5th century Nagaoka via standard trade routes between China, Korea and Japan. It was an established stop, thanks to its convenient proximity to navigable rivers. In fact, two centuries later the ancient city of Nagaoka-kyō, part of the modern city of Nagaoka, would be made the capital of Japan (from 784 to 794) because Emperor Kammu thought the new location would make trade to and from the capital easier. That theoretical advantage turned out to be a major disadvantage in practice. Constant flooding of those rivers drove the Emperor to move the capital again, to Kyoto this time.