From the archive
Ancient Roman coins found buried under ruins of Japanese castle leave archaeologists baffled
Original source: www.independent.co.uk
Archaeologists were left baffled by the "strange" discovery of ancient Roman coins buried in the ruins of a castle in Japan.
The four copper coins were retrieved from soil beneath Katsuren Castle on Okinawa Island, and were originally thought to be a hoax before their true provenance was revealed.
Discussion
This could be a gift from a trade ship, one common way for totally unrelated objects end up in ancient places. Some time back, a collection of tiles depicting biblical events was found in a Buddhist temple in Sri Lanka. Many archaeologists had the opinion that they were gifts from a foreign trader.
this makes sense. if there were real trade I think the evidence would be large than a few coins.