Another aspect of historical context, on 31 March 1854 Commodore Perry negotiated a trade agreement with Japan. This first trade agreement wasn't so advantageous for foreigners and mostly favored the local Japanese with an exchange rate of 1:1 United States Dollar to Japanese Ichi bu (which was worth about 0.34 cents). This lasted more that five years until on 29 July 1858, Mr. Townsend Harris, First Consul-General of the United States of America to Japan negotiated a new trade agreement fixing the exchange rate and setting a new medium of exchange the "Mexican Dollar". The new treaty was to come into full effect 4 July 1859 and in total favor of the United States. The new exchange rate was 1:3 Mexican Dollar to Japanese Ichi bu. Once the agreement came into full effect Japan experienced a mass exodus of gold coins with a ratio of 4:1 Japanese Ichi bu to gold Koban, worth twelve Mexican Dollars outside of Japan. Since the opening of the Japan many large gold coins such as Kobans, Obans and Goryobans began leaving the country as they commanded a 70% profit outside the country. This could account for their scarcity in today's market.
Estimate: $8000.00- $12000.00