Yuan Dynasty, 2 kuan cash note, ND (1335-1340), black text on grey mulberry bark paper, red seal top center, two strings of 10 cash coins at center.
This note was sold for HK$1,200,000 (US$154,025) plus buyer's premium at Spink's January 22, 2011 Hong Kong auction. The price including buyer's premium is HK$1,405,050 (US$180,349).
This Yuan Dynasty 2 Kuan (1335-1340) note predates the more well known Ming Dynasty 1 Kuan note by several decades.
The earliest paper money in the world was produced by the Tang Dynasty and the Sung Dynasty (618-1279) for the sake of practical expediency. These "flying cash" notes (called because they blew away in the wind!) were for local use, mainly in Szechuan, and could be converted into cash. Unfortunately, none of these earlier notes has survived. The practice of using paper money was continued by the Chin Dynasty (1115-1234) who established a paper currency bureau in Kaifeng. Later after the Mongol invasion of China, the Yuan Dynasty (1280-1368) carried on the practice of issuing "paper currency". But due to excessive printing, the value of this currency was severely diminished. Examples of the Yuan Dynasty notes are extremely rare and the condition tends to be poor. This note is exceptional for the type and is an important discovery.
Source:Some Interesting Facts About Paper Money