Why is the era called Wadō? Because somebody in Musashi province dug up copper. On this day in 708, the court recorded the first order for the Wadōkaichin, Japan's oldest official coinage, under Empress Genmei — and the years themselves were renamed after the metal. Wadō: harmony-copper. (Imagine renaming a decade after a mineral. Imagine the stationery.)
The traditional Japanese date is the tenth day of the eighth month, so the 29 August you'll see in the books is the tidy conversion. And the coin's claim to be first has softened a little: Fuhon-sen found at Asuka appear to have been made from about 683, which makes Wadōkaichin the oldest official coinage rather than the oldest coin. A fine distinction, and I love a fine distinction.
The sign below stands at the Wadō ruins, on a leaf-covered forest slope where the copper came from — a quiet hillside for something that renamed an era. And here's the part I think about most: minting money is the easy half. Getting anyone to take it is the hard half. Within a few years the court was offering promotions in rank to people who accumulated coins, which is a magnificent way of saying: please, we made these, do use them.
Pip, my favourite bit is that the court had to publish exchange rates in rice, because rice was the money everyone actually trusted. You can eat rice. Nobody ever made supper out of a copper coin, though I imagine somebody in 708 tried.
Pip, the four characters read Wa-dō-kai-chin, and scholars have been arguing over that last one for a very long time — whether it is chin or hō, and what it was meant to mean. A coin that renamed a decade and still won't quite tell us its own name.