经过春秋时代的长期战争,许多小的诸侯国不复存在,几个大的诸侯国日益强大,争战不休。到了战国时期,“上无天子,下无方伯,力功争强,胜者为右”。诸侯国为获取更多的土地、财富和人口,彼此之间不断开展兼并战争,争夺生存空间。战况空前惨烈,各国统治者都在寻求在竞争中生存下来的办法。克敌取胜之道,首在富国强兵, After the long war in the Spring and Autumn Period, many small vassal states ceased to exist and several large vassal states became increasingly powerful and fought endlessly. To the Warring States Period, “No Son, no Fang Bo, striving for power, the winner is right ”. In order to gain more land, wealth and population, the vassal states constantly carry out merger wars with each other and compete for living space. The fighting is unprecedented in tragedy, and rulers of all nations are seeking ways to survive the competition. The enemy to win the road, first in the rich and powerful soldiers,