For well over three hundred years the currency of choice in East and Southeast Asia was the Mexican Silver Dollar. When a merchant in Java did business with a trader from the Spice Islands, the transaction was usually completed with silver dollars minted in La Casa de Moneda de México, the first mint established in the Americas. British traders along the Chinese coast during the 1700-1800s used the ubiquitous silver dollar, which they called in slang terms “Mex.” Even Mao Zedong paid his communist Red Army forces during the Chinese Civil War in the 1920s and 1930s with the same Mexican silver dollar.
When Spanish explorers traveled west from the New World, they established a presence in the Philippines in the early 16th century. The Philippines were a Spanish colony, but they were administered and governed from Mexico. Manila Galleons ran regularly between Acapulco and Manila from 1565 to 1815. Each year upward of fifty junks would sail from China to meet the galleons in Manila, where precious Chinese silks and tea would be traded for Mexican silver dollars. This trading route was called in Spanish La Ruta de la Plata, or the Silver Way. Most of the silver minted for Mexican dollars was mined in Peru and in Mexico. In the first part of the 19th century, one-third of all silver produced in Mexico was sent to China by American traders, hungry for Chinese goods. These coins became so important, that by the late 19th century they began minting the coins in China, as well. Some historians claim that the Mexican silver dollar was the first global currency.
Up until World War II Westerners living in China were using the Mexican Silver Dollar in daily transactions. This is why in my novel Above the Water the protagonist Harry returns home to Texas from Shanghai in 1941 and brings some Mexican Silver Dollars as souvenirs for his young cousins.