Centralization of the south and increased industrial devolvement led to a booming economy that made the Song an even more tempting target for northern invaders. Now that peasants lived in densely populated regions in the south they became “were drawn more deeply into commercial networks selling their surpluses and buying charcoal, tea, oil, and wine” (illustrated 141). Family’s that would previously only grow one grain began producing a wide variety “farming families whose main crops were grain frequently could engage in small-scale sideline production of products like wine, charcoal, paper and textiles, which they could sell through brokers”(illustrated 141). As more families produced more goods they would have to find a market in which to sell it in “Various businesses are designated by the word “company”, which is a taxation category imposed by the government and is used for all businesses dealing in commodities, regardless of their size” (sourcebook 179). The trading companies that formed as a result of an increase of commodities would send goods all across the countries, creating a national market for goods. The rivers and roads would flow with goods and money. Kaifeng is a city that sat between two water ways and enjoyed great economic prosperity, “Here [a market place in Kaifeng] we find pearl, jade, talismans, exotic plants and fruits, seasonal catches from the sea, wild game-all the rarities of the world seem to be gathered here. The food and commodity markets…are all crowded and full of traffic” (sourcebook 178). The Song’s migration to the south, denser population areas, and intensive development of the area allowed for great economic success and prosperity.