The Numismatic Bibliomania Society



The E-Sylum: Volume 26, Number 15, April 9, 2023, Article 29


The Defense Visual Information Distribution Service published an article on the Japanese envoy's first visit to the U.S. Mint in 1860. Interesting event! -Editor

  1860 Japanese visit to U.S. Mint

Visit of the Japanese to the Philadelphia Mint, June 13th, 1860. A 19th century illustration from Frank Leslie's Illustrated Newspaper.

In 1860 Japan's Shogunate officially sent 80 samurais to the United States to establish a diplomatic and economic relationship with the White House. Their primary mission was to ratify the Treaty of Amity and Commerce Between the United States and Japan. Signed in 1858, the treaty enabled Japan to trade further with more foreign countries, which the government had long restricted to the Netherlands and China for nearly 250 years. The 1858 treaty made Japan incorporate into international relationships both politically and economically.

The Japanese envoy had another mission in the U.S.; to survey the Mint and American monetary system. They stopped at the U.S. Mint in Philadelphia after the ratification exchange in Washington D.C., before they visited New York.

Japan had been troubled by an outflow of gold since Japan had agreed upon the Kanagawa Treaty six years earlier, in 1854. This treaty initiated an economic and mutually beneficial relationship with the U.S., allowing Americans to reside on Japanese soil and engage in economic activities temporarily.

Another problem was the money Japan had circulated in its market. The monetary system was based on three kinds of coins — gold, silver, and copper. Each type of coin had a different method of denomination, which made things more complicated, mainly when they traded with other countries.

Under an agreement with the U.S General Consul Townsend Harris in 1858, Japan had consented to a 1-dollar silver coin (Mexican silver, which was used for domestic and international money at trades), which equaled three 1-bu Japanese silver coins in exchange, with which Japan was not satisfied. That was because Japan's monetary system was based on three separate trimetallic systems: gold, silver, and copper. In measuring a 20-dollar U.S. gold coin, for example, against the value of Japanese silver bu-coins, one dollar nearly came to the value of one bu silver coin.

Harris insisted that foreign currency be circulated in Japan, but Japan was hesitant about having foreign money in its market. Consequently, with a compromise, the two parties concluded that the exchange rate of one Mexican silver coin be three Japanese bu silver coins, based on the condition that the exact weight equals the same value.

Put another way, according to a research paper titled On the Monetary Unification in Japan, published in 2019, while the ratio of gold to silver in terms of values in Japan was 1:4.6380, the ratio in the U.S. was 1:15.3778. This alchemy tripled the value of Mexican coins when they were traded in Japan.

Using this system, one could cash in on the Japanese monetary exchange system by moving Mexican coins through Japan, allowing foreigners to increase their money's value quickly, and moving Japanese gold out of the country and into the world.

One of the most insightful Japanese envoys was Kozukenosuke Oguri, who acted as an inspector/censor and overseer of Japan's diplomacy. At the Mint in Philadelphia, he demanded clarification regarding the amount of gold and silver used in both Japanese and American coins at the Mint to determine the real values of cash from each country.

One American, an author and educator, Patterson Du Bois depicted the event in a book, The Great Japanese Embassy of 1860 as the following:

Oguri produced a sort of steelyard of ivory with which he proceeded to test our weights against his own. The censor also brought forth an abacus or counting machine consisting of fifteen rows of wooden buttons sliding by five on parallel wires. Quite in accord with these crude and antiquated methods was the demand that the gold cobang (about as big as the palm of the hand) should be assayed not by a sample cut from it, but by consuming the entire piece. Three cobangs were thus tested and to satisfy the strangers, also a United States gold dollar. Notwithstanding the cumbrous method of using an entire piece the results were exceedingly satisfactory.

Later Oguri and his men thanked the officers of the Mint for their courteous attention, expressing satisfaction with the results, and promising to lay the whole matter before his government so that a system of exchange could be arranged between the two countries, said Du Bois.

Patterson Du Bois was an assistant assayer at the Mint and son of 48-year Mint stalwart William DuBois. His 40-page monograph includes about eight pages of text on the Mint visit (p252-260), for which he was physically present. -Editor


"Preliminary formalities being over the occasion was so extraordinary that a messenger was quietly despatched with orders to go to a nearby grammar school and procure a release for the day of three pupils, sons of the assayer and his assistant, bring them to the laboratory where their education might take a rare turn in a leisurely and close contact with the ambassadors and their attendants. I was the youngest of those three boys, and I am now drawing on memory which is both stimulated and held in leash by certain mementos, personal notes of the assistant assayer, various public prints and official documentary memoranda.

"Entering the little weigh room attached to the laboratory the astonished youths saw the first and third ambassadors (the latter known as the censor), a stout functionary known as the governor, two interpreters—one Dutch and one Japanese—and perhaps one or two attaches, and a prince travelling unofficially for pleasure but in company with the embassy."

To read the complete article, see:
Japanese envoy's first visit to U.S. Mint in 1860 (

To read the complete paper on the Newman Portal, see:
The great Japanese embassy of 1860 (

Garrett Mid-American E-Sylum ad08b

Wayne Homren, Editor

NBS ( Web

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