Postage stamps and postal history of Costa Rica change in currency from "Reales" to the new Pesos and "Centavos", the issue of 1863 was surcharged with new values for postal use: 1 Centavos, 2 Centavos, 5 Centavos (all over the Medio Real stamp), 10 Centavos (over Dos Reales) and 20 Centavos (over Cuatro Reales). The 5, 10 and 20 Centavos were also surcharged "U.P.U." Costa Rican stamps were issued overprinted "Guanacaste" in 1885-89 following war with Nicaragua over the sovereignty of Guanacaste. The first issue in the new "Colón" currency was dated 1900 and put into circulation in 1901. It consists of ten stamps with values ranging from
Global silver trade from the 16th to 18th centuries to coins in the early period of the Ming Dynasty. The Ming paper currency eventually failed due to self-imposed inflation along with an inability to stop the production of counterfeit bills. The Ming attempted to produce copper coins as a new form of currency, but production was inconsistent. Hence silver became of high value because it was a valid currency that could be processed abroad. The bimetallic ratio of silver to gold was about two to one, which meant that European and Japanese merchants made a large amount of profit. In the 1640s, the bimetallic ratios in China converged with