Ancient Roman Coins Found in Japan

At an archaeological excavation by a Japanese castle, four old coins believed to be from the Roman empire has been found. The research is still going on, nothing about this find has yet been published in a scientific journal. It still looks like the coins have been lying in the ground in Japan for many centuries. If the coins have reached Japan in ancient times, it must be a fantastic discovery. Imagine the trade, this long ago, from Southern Europe to Japan. It will be nice to know what the researchers settle as the probable year for the arrival of these coins to Japan.