While supervising and handling with the military affairs of Zhenjiang, Feng Zicai summarized a set of positive defense techniques and elastically put them to use in the anti-France war, leading to the great victory in Zhennanguan. Facts proved that in wars against foreign invasions in modern history, Feng Zicais positive defense techniques compensated for the many inferiorities in Qing armys military equipment and qualities. They turned out to be advanced military achievements which took the lead in that era.