Just when I thought I knew a bit about Japanese coinage, I stumbled upon an interesting article. Out of all possible places to research, it's wikipedia. Reason why I am posting in the US forum? Of course, it has to be related to the US!
Quick introduction. Japan Mint in Osaka was established in 1871 (Meiji 4). Note of the timeline - Japan at this time was using a different calendar called Tenpo calendar (I did not know this!). As Japan was modernizing it's coinage, it hired expertise from England. Mint equipment is second hand as it came from a very short lived mint (1866 - 1868) in Hong Kong (when it was a British colony). This is where the timeline gets confusing. There are coins dated Meiji 3 (1870) - maybe to illustrate that this was the original planned year? Maybe it did happen in 1870 because of the Tenpo calander? Need to do more research... Back to topic.
The amount of coins Japan mint supposedly struck is impressive with a wide array of coins in 1870 - 1871. 1/2 sen, 1 sen, 2 sen, 5 sen (2 types!), 10 sen, 20 sen, 50 sen, 1 yen (silver), 1 yen (gold - dated 1871), 2 yen, 5 yen, 10 yen and 20 yen. Quite an impressive feat to issue 14 different types of coins for a brand new mint! (1 rin coin was struck later in 1873) The big question is - were all of them struck in Osaka Mint...?
A line popped up when I was reading about Japanese 5 yen.
Five yen coins were first struck in gold for the Japanese government in 1870 at the San Francisco Mint. During this time a new mint was being established at Osaka, which did not receive the gold bullion needed for coinage until the following year.
https://en.wikipedia.org/wiki/5_yen_coinThis is the first time I read US mint struck coins for Japan. Wow. The question is why? Why not from Britain when the Meiji government struck a deal to setup 'new' mint in Japan? The question doesn't end there - if there wasn't enough gold bullion to struck the first Japan machine struck gold coins, did San Francisco mint actually struck more than just 5 yen gold coins?
Have been doing some research and early San Francisco mint annual report has some interesting reports about coinage from overseas, in fact VERY detailed. Oddly I am struggling to find the exact reference of SF mint minting gold coins for Japan.
https://fraser.stlouisfed.org/title...1870s#701446The relationship between SF mint and Japan doesn't quite end there... There is a rather rare if not unique mint error quarter. 1972 S quarter overstruck over Japan 10 yen (!). Error coin from Mike Byers
https://minterrornews.com/issue27.pdf1972-S PROOF 25c struck on an already Japanese 10 Yen. A proof double denomination on a foreign struck coin, Only 1 known PCGS. The US has never officially minted any coins for Japan. This coin was probably snuck into the Mint, overstamped and the secreted out of the San Francisco facility
Did San Francisco mint strike coins for Japan? I thought I would be able to find it in US mint report but it seems to be illusive. This got me intrigued. Maybe someone can add more information!
Posted 01/23/2026 12:05 pm
