In Japan, in the past, they did carry the coins as a pack of 100, thats why they have a hole in the middle, they took this habbit from the Chinese, and i think the chinese took it from the time when they used shells as money.
And someone, dropped 2 of this 100 coin packs over there, with time, it got dispersed and scattered around. About 2m x 3m area with no metal trash at all.
The funny thing is, this place is kind of a part of a long natural bridge, there is a main river on the left hand side, it goes about 7m straight down.
On the right hand side, there is a small river that flows into the big river, and there it also goes straight down for several meter.
The bridge is like slope, formed like a snake, sometimes it only has 2m wide, but on the both sides it goes straight down for several meters.
I did follow this slope, and, at the start of the slope, someone dropped the coins, if they would have rolled down, the river would have eaten them. But, with time they dispersed.
Also, this slope, is so fragil, one day, when a strong Taifun comes, it will just get washed away, so, i am quit lucky.
From the age of the coins i guess this must have been about 200 years ago.
At this time, this person had 2 coins they already used about 800 years, made in china, paid by Japanese with gold, or taken through japanese piracy ships.
But, sadly no gold, I want gold coins....