长平之战是战国时期规模最大、战斗最激烈、影响最深远的秦赵之间的一次大战。纸上谈兵，是指只会空谈兵书，不知通变的赵军主将赵括在这次战争中使赵军惨败的典故。战国时期，秦国经过商鞅变法之后，国力日趋强大。至战国后期，秦国成了七国中势力最强大的国家，它积极向东扩 Changping war is the Warring States period, the largest and most fierce fighting, the most far-reaching Qin Zhao a war. Papers on paper, refers to only empty talk martial arts, Zhao Tong, I do not know Tongchao Lord Zhao in this war Zhao defeat allusions. During the Warring States period, after Qin Shang changed the Shang Dynasty, the national strength became stronger day by day. In the late Warring States period, Qin became the most powerful nation among the seven countries, and it actively expanded eastward