Sycee were small silver ingots used for trade in 16th through 19th century China. Stamped with the production date and silversmith's name, they were preferred to what were then dangerously unreliable government currencies. Both sycee and bad currencies were products of the Mongol invasions.
Merchants and regional governments in China issued paper money before 1000 AD. The first state-printed paper notes appeared in the twelfth century, backed--ostensibly--by bronze coins of corresponding value. Printing money enabled the Chinese to export coins to Japan, who also used them for currency. Within decades, the Chinese government decoupled paper money from coin. Bills washed into the economy, successful in the short term.
It was around this time that the Song dynasty engaged the Mongols. Like any fight against the Mongols, it was a miserable mistake (ask Crassus of Ancient Rome). China was brutalized, not before inducing a recession with its printed money. The Mongols--the Yuan dynasty, now--seized on the concept, printing its own.
This hyperinflation is the seed from which the next centuries of financial uncertainty grew. The Yuan dynasty's money was worthless by the time of the Ming overthrow a decade later. The first Ming emperor issued new coins and outlawed paper money. Then, finding China's copper mines exhausted, he issued paper bills and stopped producing coins.
Ming money, too, was worthless within a decade. Mostly because of political intrigue, a succession of Ming emperors issued new money and outlawed the old. Desperate merchants took to trading in 400-year-old Song coins, along with obvious counterfeits.
By the sixteenth century, uncertainty over bronze coins and paper money was such that traders carried sycee, weighing them at transaction and clipping needed sums with shears. Silvermasters charged a fee to evaluate the silver's purity at transaction, usually cheating both parties.