One important invention that was created in the Song dynasty was the invention of paper money.
Before paper money, people in China used metal and stone coins, which were bulky and could get really heavy at times. However, the paper money made it much easier to carry currency over long distances for trading without the large weight that metal coins had.
This invention affects the whole world today, as many countries have adopted the concept of paper money and still use it. Let me know if you need any clarifications or extra info, thanks!
~ Padoru
