Step 1 : Introduction to the question "Which country introduced paper money?"
...The Chinese began using paper bills during the Tang Dynasty (A.D. 618–907), primarily in the form of privately issued bills of credit or exchange notes — and used it for more than 500 years before the practice began to catch on in Europe in the 17th century. The Chinese found the weight of coins to be cumbersome and figured that printed money would be more efficient. It makes sense, considering that China also invented both paper and printing. It took another century or two for paper money to spread to the rest of the world.