Answered by Irina from Mexico | Apr. 14, 2013 20:53
The first reason is that the fatuous rule or tyranny of Shang dynasty, which provided a good opportunity for Zhou rising, because people had not been satisfied with Shang for a long time.
The second reason is that Zhou had relatively agriculture level, which happened to meet the demand of people whose elementary need was to feed themselves up. By gaining the support of people, they rose quickly.
And other reasons should be the humanand wise measures and regulations that were carried out!