 Major cities would grow into silk, porcelain, and cotton centers providing work for a lot of people and made inter-regional trade easier so merchants and consumers participated in a local market system to exchange goods and services with one another.In addition, improvements in agriculture contributed to economic growth as new strains of rice resisted droughts and disease, and fertilizers allowed double cropping of fields with better irrigation techniques to help farmers produce greater surpluses.The use of copper-alloy coins greatly facilitated Japanese estates to sell extra produce in the marketplaces.